If you want better public transit that optimizes to serve only profitable routes, privatize it and "let the market go nuts".
I'm generally nearly fanatically free market, but there are elements of mass transit that need to serve unprofitable routes, just like the USPS, legacy POTS telephone, and electric company [all of which have significant government restrictions that ensure they serve unprofitable areas].
I don't see any public transit serving the farms just outside my city even though those farmers would benefit. Until public transit serves them your argument is invalid.
Private public transit companies will operate some unprofitable routes letting the profitable routes subsidies them. They know that in some cases the customer satisfaction that comes from people being able to get to those places with little demand is worth running unprofitable routes. I won't speculate on how many they run - other than to state that they will constantly reevaluate all such routes)
I'm generally nearly fanatically free market, but there are elements of mass transit that need to serve unprofitable routes, just like the USPS, legacy POTS telephone, and electric company [all of which have significant government restrictions that ensure they serve unprofitable areas].