Tech might be the only high-paying (or, hell, reliably middle-class white-collar) field where this is true.

Not true tbh. Tech was the first place where that was the case, but increasingly high-paying professional jobs don't require an undergraduate degree, since its losing its value as an indicator of ability.

Postgrad degrees still have a lot of value, and open a lot of doors. There are things I learned in my Master's that I probably wouldn'tve been able to get at a deep level working in industry, and for that same reason I want to go for a PhD (even if it might be ill-advised in these times).