Huh. This is making me realize that perhaps my situation is more bizarre and unstable than I realize...

How uncommon is it for someone with no highschool diploma (GED), or college diploma to get a job as a software engineer at a Fortune 500 company? Am I completely fucked if I ever lose this job? It's my second SE job...

Like OP may have been hinting at, I had a really fucked up family situation and this path was the only one that I could take- should I plan on going back to school just for future job market security?

I wouldn't worry too much, 20 years ago when I entered the industry (with a philosophy degree), the adverts which emphasised degree pedigree over experience were common.

I have watched that diminish over the last 20 years.

The unspoken secret in programming is that a CS degree basically signals absolutely nothing about programming skill. You can get a 1st in CS and be a rubbish programmer, you can get a chemistry degree and be an amazing one. A lot of CS is utterly irrelevant to programming, and the vast majority of programming skills are not covered by CS degree.

Once you're past 2-3 years experience it stops being relevant, before that it's a way to filter CVs by managers who want to pretend their CS degree wasn't a complete waste of time.

If they're asking for a CS degree for a senior role it's basically advertising they're a clueless company.

I'm in the market now and I honestly don't think anyone even looks at the education section of the resume if there is applicable work experience following it. After 10+ interviews in the past couple of months, education hasn't been mentioned once in an interview, and my unofficial transcripts have been requested one time prior to and interview.

I'm in a similar boat. I dropped out of uni for reasons (a bit of a story, I can tell it if you buy me a beer) and ended up making a career out of software engineering.

The main thing to do IMO is spend time building a network. A recommendation in the right place at the right time can open doors that would otherwise be closed to you.

School is an option, but the opportunity cost has been too high so far for me. Though doing a freelance PhD thesis probably wouldn't hurt.

It's true that the game is probably absurdly complex, but how did they never profile loading times?

Actually the Mac client supports it for some reason.

How can a self-taught individual such as myself begin to learn the theory presented in the academic computer science world without enrolling in a college or university?

If talking about physically going to university or college, take a class online.

If you don’t want classes in general, go to course sites for universities and check the textbooks they use/reference.