Youtube has incubated many multiples the number of creators than PBS member stations despite not providing upfront funding. Most creators don't start out from corporations or business loans.
She got her start by being "Shitty robot queen" on reddit, not youtube.
The "PBS spacetime" channel exists, so they're doing something right.
If it was properly funded? Quite possibly. If it had the same funding as Youtube's ad revenue then I think you'd have all those, but maybe a lot less of PewPewDie and Dude Perfect.