Finding good developers is hard.
I don't know about the US, but there seems to be a genuine skills shortage in London. I have seen technical tests and interviewed literally hundreads of people over the last few years and only a handful were good enough for a job.
There were several people who passed the online technical test, but when faced with a technical phone interview, the large gaps in their knowledge quickly become apparent. Of the few that make it through to a face to face interview, a lot seem to have, how shall I put it, poor communication skills. I'm not talking about the standard interview nerves everyone gets either. I am talking about a genuine inability to articulate them selves. If you can't speak technical to me, the chances of you explaining issues to a pm or client are minimal.
Harsh, but true.