Be careful what you wish for....
I don't like shooters much (just not my thing) but most of these CoD kind of games aren't written any worse than Halo. From a writers' (they have a few of them) standpoint, the process is probably the same - I'm sure scenario design works out the levels and gameplay before the story. If you think WWII or the current crop of generic shooters is bad, play the highly original 50 cent: Blood on the Sand.
It could be worse. Hysterically worse. The plot to that game involves 50 cent going to the middle east to stop a terrorist who stole a priceless jeweled skull using rap music. Or something like that.

No, laziness is more to the point.
A lack of creativity or gumption does not equate to a lack of a talent.
Now, once we get to the stage of super photo realistic mega textures with ice cream, and the artists/designers literally copy and paste everything. Then, and only then, will I say there's a lack of talent.

If you lack creativity, then you have no talent to be a designer, an artist.

I liked "Bridge on the River Kwai" too. ;)

Making any kind of historical fiction is difficult too for the same reasons, but at least in that genre a lot of answers are provided for you. Speaking for myself, I find that it's usually easier to apply my imagination than to seek out existing information.

You're taking it seriously? :P

A good, realistic, well researched war game takes a heck of a long time and a heck of a lot of effort to create. That being said, most war games are not well researched, they just use familiar things (Sherman or Tiger tanks, whatever), bung stats onto them that make the game fairly balanced, and call it good.
Familiarity is probably one reason why the games are popular. Someone can pick up a WW2 game and know roughly what everything can do, and they know what to expect.
Take a look at the Storm of War: Battle of Britain development process to see something with effort and research put into it.

Army Men. Zombies. Space Marines. Knights. Wizards. Ninjas. Racecar Drivers.
That about sums up videogames right there. As much as I love games, even some that rely heavily on these old cliches, it feels like ingenuity is a rarity in the world of games. It gets hard to tell one game from another. I think this is why indie developers have become more popular recently. Games like Zeno Clash, Braid, and World of Goo have all created interesting fantasy worlds and added a few interesting new game mechanics. Mainstream games get increasingly realistic, dramatic, and finely tuned in their genre, but there aren't many that really travel new ground.

You forgot plumbers. :)

I wonder if there isn't any more genres to be made. They may not travel new grounds because there isn't anymore that is new maybe................
An example may be Avatar, nothing overly original. It's just well done with newer technology. Games are following movies in this aspect in that many games will have certain similar others no matter what nowadays.

I think there are new genres still to be created. We've seen a few games in the past few years that did really interesting things in the gameplay mechanics that haven't been done before. The gooey construction of World of Goo, the time bending brain twisters of Braid, the creative puzzle solving freedom of Crayon Physics Deluxe, or the dimension jumping of Portal. There are still creative ideas out there that change the game. I think there is kind of a natural barrier to innovation though. If a game is too radically different from standard control schemes, the learning curve is too steep for gamers to hold interest all the way through the tutorial level. I think many gamers actually like convention. They want to have the WASD + mouse control in their FPS games. They want the classic hadouken joystick movement to execute a special move in whatever fighting game they play. Basically, they want to already be pretty good at a game before they even start playing it. Rock the boat too much in the control scheme, and they are lost and think the game isn't fun. So, the new genres don't immediately develop, but through small introductions of new ideas, they catch on. For example, people love the gravity gun of Half Life 2, which is a really unique way to add physics puzzles into a tried-and-true first person shooter setup. As more games add tweaks here and there new genres will likely develop.

Not a "true" artist/designer.
But you still might have the talent to do as you're told and build meshes, create textures, animate et cetera.
That's all I'm saying.
And you wouldn't be surprised at how many artists are actually out there, both in the field of PC games and otherwise, that actually lack creativity yet make more than those that have it in spades.

Well some convention breaking games like Dawn of War 2 are so different they get bad reviews. Some mechanics are not used in mainstream games probably because those are faulty mechanics as DOW2 showed.
Meh, maybe we did hit a wall where each innovation made makes one less to be made and I agree with that theory. We might be nearing the end of this cycle or at a plateau point where once past it things are easy to think of again or even harder. Who knows..........

I think that sums it up. Less of a "learning curve" compared to say, a hardcore sc-fi game (with the exception of Star Wars\Trek games maybe).
Also the popularity may come from the setting. The US has a strong national pride, and WWII is often considered "Their finest moment" in the eyes of many Americans. I can see why the games are so popular and profitable; at least in our country.

I'm not sick of any genre, it's just when the game feels stale and not fun is when I don't like the games. Fun and enjoyable is most important to me when it comes to any game. I Had no interest in MW2 because the multiplayer seemed to o reduced compared to other multiplayer games and while the campane looked entertaining for one playthrough, It was too short and too expensive. Maybe if it was $20 or less then I would consider it. Just like the original looks appealing now because it is not as expensive