I've worked with a lot of good kids and in no way do I think money is the issue. Trust me, no club or teacher is going to turn away a potential professional tennis player because of lack of funds. Having a kid like that brings in 20x more juniors and publicity. Heck, a lot of the good kids at academies dont have to pay because they bring in other kids. Now, I'm sure their are a lot of kids playing small college or mid major d1, they could have been great college players but couldn't afford the grind. I was one of those kids. But truly elite potential gets noticed and wouldn't be turned away.
I do think "tennis" in general gives off an expensive vibe to low income parents , so they choose to never even start playing. This perception is probably untrue, but very real. I have parents all the time just assume they cant afford before even looking into it.