Maybe those companies that have trouble finding good developers are using HR-bots and headhunters who are looking in the wrong places, focusing too heavily on checklists, and asking the wrong questions?

The funniest trend I notice these days is that headhunters do the reference checks for hiring companies. It's in a headhunter's best interests to make sure a short lister gets hired. Yes, headhunters have minimum-term guarantees to keep their fee, but I do notice that many companies are also slow to fire someone who isn't blatantly incompetent, so there's a good chance that a headhunter will still win by placing a dud.