Inspiration. People work hard on things that inspire them. That inspiration leads to advances.

> why is game dev worth devoting the massive amount of man hours and natural resources to?

GPUs were arguably made for games and now they'd enabled all kinds of non-game things.

I don't remember all the things that space exploration has brought but a quick search brings up this from JPL

https://d2pn8kiwq2w21t.cloudfront.net/original_images/infogr...