The seemingly maniacal obsession with ESL/ENL differentiation is a competitive strategy.
Umm, yeah, that's just not true. Nobody is being maniacal here. It's about the risk associated with scammers. Unfortunately, there are more scammers from foreign countries. It is a very useful heuristic to just simply exclude foreign-based writer when most of them are scamming. Again, this is unfortunate for those ESL ghostwriters who are legitimately trying to gain a foothold in this illegitimate industry.
Also, I am competing with you. The academic ghostwriting community does not need to invent or create a straw man as you have here. Generalizing to the native English speakers and bashing them isn't going to help your cause.
It is absolutely clear, at least to me, that a lot of my clients would be better served by an ESL writer. And I'm just as sure that the opposite is often true. So maybe a better question would be: How is it that we pair the right clients with the right writers in a business that is simply about the bottom line?
In the end, producing an excellent academic paper often does not require a pedantic approach to grammar or language usage, and it certainly does not demand native-level apprehension of English.
I find it hilarious that you are being just a tad pedantic here.