Recruiting is essentially advertising / marketing for a company about a job opening. Email / spam is direct marketing, which can work sometimes for recruiters. You also can do web marketing, like hackernews does for its YC companies, but recruiters would need to advertise on say, Linkedin, Stackoverflow, etc. Beyond that, you have your organic marketing, which is word of mouth, or friends of friends, but then you usually bypass an actual recruiter if you go down that route.

To me "fixing" tech recruiting is trying to come up with new ways to advertise something, which I believe is an evolving process but not something that can ever truly be "fixed".