Earlier quoted context omitted.
Very few engineers (as a percentage of all engineers) even in the Bay Area earn that much (base, all-in, or otherwise). Typical non-management compensation (all-in) is going to cap out ~15% or more below $300k. I've taken several salary surveys and done plenty of research through publicly available sites (e.g. glassdoor, linked in, payscale, etc.). For what it's worth, my all-in compensation is well below $300k/year…
I'm not saying these salaries are normal - I understand I am highly paid. My point is you can typically do better financially in the Bay Area if you are great at what you do. And something I think a lot of people don't appreciate is that by moving to the Bay Area you are more likely to open yourself up to those opportunities in the future. I would have a completely different career had I never moved here.
Definitely agree with respect to opportunities, though. Even at double the cost of living or slightly more, the doubled salary means one is saving more in absolute terms and has access to a much better job market.