Dedicated Internet access is a thing, but it's expensive; and I'd argue that even that is oversubscribed if you go far enough up the chain.
The only way to get internet access that’s not oversubscribed is by renting (or pulling your own) layer 0. By that I mean either renting a wavelength between certain PoPs or just pulling your own fiber.
As long as they make a fair guess and I get my bandwidth whenever I want, all is good.
That seems to be the case right now.
Dedicated internet access is a different thing, I agree, it also provides different guarantees, support, etc.