Ya, I've been the victim of "couldn't balance a B-Tree fast enough so you're not hired but you'll never see a B-Tree at work."

You mention that there isn't a better solution. IMHO, I disagree.

I think Github has figured out a way. They've been around 5 years and haven't fired anybody and nobody has quit.

Most firings are due to a job / job skill mismatch. At Github, they do a week long paid interview so both sides really know what they're getting into.

I don't work at Github, but am such a fan of their company.