I think you may be painting a simplistic picture, and are making an implicit statement about my experience.

I have never worked for a software company that didn't value it's developers or their contributions. Quite the contrary, in fact. Benefits, high salaries, flexible hours, work from home all on top of routine praise and a very supportive work environment. None of these will guarantee that a top employee won't be attracted to possibilities and challenges elsewhere.

We've got junior developers in the high $30K range and senior in the mid $60K range.

It is frankly unimaginable that a highly qualified developer would be paid $60k in the DC metro. The cost of living is easily on par with many parts of the SF Bay Area. It's quite possible that our standards for "senior developers" are different, but I'm quite confident my numbers are correct.

As far as $30k for junior engineers - frankly I know data entry technicians in Virginia who are paid that much or more.