Most companies who are trying to 'improve' recruitment are coming from outside the industry and are tackling it with an engineering mindset. It's an easy trap to fall into, as it seems like a simple two sided marketplace, however that is not the case.
It needs to be approached more like legal tech, with experienced recruitment professionals working alongside engineers. The complexities, nuances and psychological factors need to be understood. There's a reason recruiters are so expensive after all.
All the companies you have mentioned above just quickly built a simple marketplace and then advertised them like crazy to gain users, they never actually solved the inherent problems within recruiting.
It definitely makes sense for tech to do a lot of the heavy lifting. I actually think humans are critical for recruitment (having done plenty for my company), but I agree that there are aspects that humans will never be able to do at scale. Using AI that has access to so much publicly available data would vastly improve the industry. Good luck WorksHub, maybe your AI can help me find great staff!