I’m surprised that this doesn’t get talked about more - I’ve worked with plenty of women, minorities, and immigrants at large tech companies, but I can’t recall a single person with a southern accent.
I recently worked with a guy from the south who had a wicked accent. I could understand him because I spent time in the military and one gets used to all kinds of accents, but no one else could understand him. He was pretty smart and I’m sure he will do fine, but his accent definitely got some mean comments. I told a few people to knock it off because he didn’t deserve them.
The other obvious missing part is African Americans, especially for tech roles. I'd be shocked if more than 1% of SDEs at FAANG are African Americans. The biggest social elevator of the past few decades and they're completely cut off from it.
I wouldn't frame it as "cut off" as much as it is "unknown unknowns."
If you don't have family/close friends in this industry and don't have any resources or the wherewithal to help you/yourself break into it, then you're kind of SOL.