I've been around both industries and the main thing they survive on is convincing engineers to stay in crap conditions because of how "cool" everything is. I'm lucky enough that the game company I worked for was run by great people, but I've heard horror stories from friends that moved on.

The equity piece is just percentages. If I go to a "startup" in series D and get 0.01% of the company, it better be a frickin' unicorn, because it'd have to sell for $1B for me to make $100k, at best. If I'm a cofounder and have 25% of the company, it only needs to sell for $400k for me to make the same amount.

Never mind that you'd make that $100k difference within a few years, being paid market rate at an established company, and probably get to go home at 5. Now imagine what happens if you put that extra $25-30k you're making into the company's matching 401k, because they actually have one. And you get real raises instead of more stock options that may wind up worthless. And if things go sour you just go to another company, because your investments aren't based on the success of the dysfunctional company you're currently working for.