OK, that's fair. I haven't been a junior engineer in Austin, so I'm estimating from what I see on hiring sites.
$130k is at the top of the SF range for a junior engineer, too, so let's call it a $40k spread. That's still entirely consumed by the difference in rent and taxes.
"Also $250-$400k is the norm for senior engineers in big companies here in the Bay Area."
On this point, you are absolutely full of it. You're talking to a "senior engineer", formerly in the Bay Area. Real-dollar compensation for elite people can get that high, but most people aren't elite. Also, I don't count future value of Magic Stock Bux as salary (nor should you).
Comments about retiring at $some_young_age are treated with the same respect as when they were coming from 20-somethings in 1998: put up actual numbers or shut up. Internet People have been ambiguously bragging about their early retirement scenarios since the internet supported bragging.