If anything, I'd see this as an example of why basic income is a good idea and people won't be spending their time just drinking their asses off.

Is this really any better?

Yes

An artist on basic income spends 300 hours working on his latest painting, is his time just as worthless as the man sat at home drinking?

I'm thinking of taking a year or two to make my own FPS with an aesthetic & gameplay similar to the 90s classics. But I'm concerned that even though there's a huge number of people who played and liked these games, they would also consider these games a product of their time and that it would be quite difficult to sell such a game.

Making a reasonable wage with a game is a lot of stress and luck. What if you approached it differently? A reasonable engineer could take a 50% pay cut and still have a living wage. Why not take a personal year now and then?

It's tough, I'm not an engineer.

To be fair, I suspect you would get at least a few people willing to pay for such a game, especially if it looked at least decent on Steam or in a Kickstarter campaign.

People wanted a new Banjo-Kazooie, we're getting A Hat in Time and Yooka-Laylee (among about 20 others). People wanted a new Mega Man, so there are games like Mighty No 9, Recore and Azure Striker Gunvolt. If there's a style of play that's died down a bit in recent years, it's pretty likely there's an audience.

So yeah, it's probably not hopeless. There likely is at least some semblance of an audience for an old school style FPS game with less cutscenes, maze like levels and a more arcade like feel to it all.

Devil Daggers came out this year. People seem to really love that game. I think you'll find more of a crowd than you think with most aesthetics. I would try to keep up with the gameplay trends though. Did anybody ever like using PgUp/PgDn to move their camera?