And those foreigners with second-rate English can only get jobs through recruiters or at training centers. Recruiters don't care if they're selling petend teachers. It all boils down to money!

I don't think it's English language ability...I seriously doubt if most Chinese schools can really judge whether our English is good or not, which in itself is kinda sad and scary.
But there are other factors that can make it easier or harder to get jobs- race, nationality, appearance, etc.- and those with disadvantages there are perhaps the ones most likely to turn to a recruiter.
But it indeed does boil down to money...