That said most routine tests are pretty cheap. A stool culture with isolation where I am is $135 if you're paying cash at the lab. A lipid panel was well under $50. It's just that you'd need to see a gastroenterologist, pay for her services, hope that she gives you a referral, and see a new one if not. This drives the price in time and money.
Historically, if you got VD -- back when it was called that -- they took the names of all your recent sex partners, tracked them down and notified them and treated them.
It was a system that was fairly effective.
Then AIDS came along and was associated with homosexuality and IV drug use. For understandable reasons, such people didn't want to name names. So the mantra became "we need better drugs."
That general line of reasoning seems to be a trend. We can't do x, y or z because reasons, and then we don't actually have an answer, basically. Hopefully, that will change.