Many actually do that job. And many others dream of doing the job.

Many truck drivers enjoy driving truck driving simulators, because these allow them to drive trucks that they can't drive in real life (ask any German truck driver, if he would like to drive a Kenworth truck) and on tours that are out of their IRL - reach (foreign countries).

Many train conductors and train drivers have set up a model railway at home and/or play train simulators on their PC.
The motivation is mostly the same as with truck drivers: broadened assortment of trains and tours (foreign countries) available.

In case of the train simulators comes another dimension into play: driving trains that aren't normally in use anymore outside of museum operation (Steam-locomotives).

The same with farmers...the simulation allows them to "own" machines and animals and estates in a scope that is far out of their real life financial opportunities.

Car mechanics usually don't get the chance to renovate/repair a 1967 Chevrolet Impala, etc. - but the simulator allows it (and much more).

What all simulation players unites is the devotion and passion to the subject at hand - be it in real life or in simulation.

No it's not a pure fantasy for some people because I have heard of people who Play American Truck Simulator or Euro Truck Simulator 2 have actually got gobs as an actual Tucker.

With them Flight Sims some of them want people to actually play them to help to learn how to fly and want them to earn their pilot's license in real life.

Also back with the Rock Band Guitar Hero Craze back during the mid 2000s (2008-2009) some people who played Drums wanted to learn how to play drums in real life.

Video games are ultimately escapism, people have long wondered what other jobs would 'feel' like, but given our limited time and how hard it is to reset your skills in work, we never get to (well, rarely) try other jobs. That's where these games come in.

I've known one person "in real life" who was super into Microsoft Flight Simulator and it was absolutely because he wished he was a real pilot with a private plane but couldn't be, so he did the simulator instead.

How true that is in general, who knows.