You messed up your third quote ;)
It’s a statement posted by joelsanda, not me.

The rights to distribute a given game's IP may likely first be done for Windows, either explicitly or implicitly. Distributing versions for Linux, OS X or Android, or any other platform may likely require an entirely new set of negotiations (requiring yet more time to complete) that may entail different demands from the IP holder/publisher. The IP holder may even want differing terms of profit sharing because they may percieve sales to be lower on a non-Windows platform. This would especially be an issue for GOG as in most cases, they'd have to be the ones actually creating the OS X/Linux port (for classic games running in DOSBox or WINE).

This is purely conjecture at this point, so don't take this as gospel. The other reason may simply be lack of percieved demand. And there may very well be technical limitations, in that they may just be spending extra additional time putting the game through their testing and compatibility labs.

Oops. Thanks for that.
I thought about that too, but I'd reckon that GOG assumes all duties for technical support of its Mac and Linux versions anyway.

Probably not, because, as you said, GOG is likely to handle this for DOSBox games.

I don't care for either because both use (and in my opinion abuse) vendor lock-in techniques. If one's product is excellent, one shouldn't need to use such practices. I also don't care for having my intelligence insulted by their advertising.

Which never stops a customer from thinking "Your game, you support it." and going to them and then complaining and maybe boycotting them after when they say "We let GOG do the Mac thing but we don't support it, you need to go to them." etc. Dealing with customers can be a tricky thing and some companies just don't want to "go there". That doesn't mean that others wont go there however either. It's just not ever just as simple as "it is doable so therefore why not do it" though. :)

Keep also in mind that often games were given away to other companies to port them, very often including the rights to publish them. So while the original publisher maybe still has the rights for the dos or windows platform it does not mean he also owns the rights for the mac, c64, amiga, nes or whatever system it was released on.

Some newer examples here are LucasArts and Warner Bros, which asked Aspyr and Feral Interactive to port and publish their games for the mac. For that reason GOG can't release the mac versions for many Star Wars games (as example Knight of the Old Republic series) or the Lego games. Like Steam GOG would also need a deal with Aspyr and Feral Interactive to do so. I'm pretty sure something like this happened very often in the past, including the good old dos time. So if there was a mac release in the past, it's less likely that GOG can release an own port, except the main publisher still owns the rights for that platform or got them back.

Btw, that does not explain why Telltale does not release their mac versions here, because as far as I know they are publisher for all their releases (win, mac iOS). Would be really interesting to know the reason here.

I didn't think of that. The original Might & Magic series may not be available on Mac because of this. But I suspect you're right about a number of the titles I see only for Windows, despite them having Apple versions when originally released.

I think Mac is facing the same fate as Amiga: one for professional one for gaming.
Adding to it the price...

Alsp, if you think about the HW processing power, PC is much cheaper for moch more and gamers can keep upgrading it for years.

Mac is more like a console: it is much difficult to upgrade and keep current.

Which is a valid point, because a lot of classic Mac game ports originally existed in a form that was very, very different from how they appear on GOG today. Then again, GOG is still traditionally seen as a company responsible for focusing on bringing back classic games. It's conceivable that people could be angry at a given publisher for poor support of a given Mac game, but from what I've seen here people usually direct the blame at GOG for a poor quality release. (The controversy and ire surrounding Interstate '76 and Carmageddon come to mind here.)

Sorry, I wasn't clear on that. I meant to say that GOG would be spending extra time testing their games, not the original game publishers.
Yeah, pretty much this. I remember when GOG actually released an OS X native port of Imperial Glory that was actually developed and published by Feral Interactive. Not long after it was put up it got pulled entirely, likely due to the fact that GOG hadn't properly secured to the rights to sell and distribute it.

That's a good point also... often companies hire or offload ports to other systems to another company and the other company may do an incredibly shitty job of porting the game over. I've heard very bad reviews of several games being ported from Windows to Linux on the Phoronix news site in the last 6 months. I think one of the bad ports was Alien Isolation, but I've heard of other bad ones too.

Yep, I think Feral Interactive was one of the companies that writes shitty ports but I'd have to dig up the news on that to be sure.

At least for Metro (Last Light Redux + 2033 Redux) games its true that gog is having technical difficulties that they don't seem to be able to surmount. The issue is per words of a gog employee (at the bottom of the linked article) purely on their side and is not a legal issue.

I guess there is a high chance that its the same with other missing mac/linux games on gog.

On that point I remember that Loki's ports were pretty hit-or-miss back in the day, but back then they were pretty much the only game in town.

Actually, Feral Interactive's one of the better porting houses I know of. They're pretty communicative and receptive of comments and complaints from their customers; one of their higher-ups is an active poster to the InsideMacGames forum, and the MacRumors Mac/PC gaming forum. For a lot of their games in the past they even went to the trouble of providing universal binary patches and OS X patches, in some cases even years after the fact. It's true that some of their ports suffered from performance issues over the years and/or they may not have brought over all of the DLC for a given game, but the former problem, IMO rests with Apple, its lagging graphics drivers and their piss-poor OpenGL support, while the latter problem is more a publisher issue.

The absolute worst porting house was MacPlay. Between the lack of patches, and awful programming (their port of Sacrifice actually required you to remove RAM from your machine if you wanted to play the Mac OS 9 version, which performed better), their ports were simply awful. The real kicker was that they were the ones who always secured the most-demanded games of their day.

Wow, that's a blast from the past. Indeed they were the only serious game in town. After following them for quite some time I was getting the urge to support the company for all of the "good" they were doing for the cause of gaming in Linux. I was debating buying just the games I wanted the most versus buying their entire catalogue to say "I support what you're doing, keep up the good work!" but before I could make up my mind and place an order... the company went out of business and went down in flames with a massive scandal of the owner not paying employees their wages and walking off with the money or something like that. I forget the details as it's well over a decade ago now but it was a pretty big bummer when it happened. Epic Megagames was trying to be Linux friendly at the time also but I don't know how far they took that as I didn't follow Linux gaming too closely for some time after that.