The abstraction layer requires the company to buy in (politically, not just monetarily). If you've been around the Fortune 500 at all, it's very common to have

The abstraction layer requires the company to buy in (politically, not just monetarily). If you've been around the Fortune 500 at all, it's very common to have large-ish, very powerful HR organizations. Taking something very fundamental away from them - the candidate pipeline - would be really unpalatable and controversial because it takes away about half the organization and a good chunk of the supply side. You aren't wrong, I'm just stating why it's not happening.