Just for a datapoint, I've never lived in the Bay Area (and haven't worked on-site for a dozen years), and I make a lot more than that as a developer. I am in no way unique. This is in fact what good devs make if we ask for it. Nomatter where we live.
Incidentally, you're right that you generally won't receive an initial offer for that kind of money. You need to negotiate for it. That is sadly another area we devs are not historically good at:
http://www.expatsoftware.com/articles/developers-should-lear...
The national median is right around $100k.
Developers that earn significantly more than that have significant ownership stakes in the company, highly desirable skill-sets, or notoriety in the field.
Personally, I prefer to listen to the person who has tried a thing and declared it possible, rather than the person who has never tried that thing and declared it impossible.
Sadly, this thread (and others like it) fill up quickly with that latter group.
You're typical mid-western Java dev is not going to get a job for $300k. Or anywhere remotely close to it. Those salaries are for very specialized roles and consultants.
Most of developers in the world aren't allowed to move to SV or Seattle and get those salaries.