A lot of ISPs were already dodging the old, weak rules anyway out of an abundance of caution. Instead of doing any direct pay-for-play, they started doing other policies that sounded pro consumer but lead inevitably to the same non-netural, corporate-controlled world.
For example, T-Mobile favoring huge video streaming platforms over smaller competition by exempting the big boys from data caps. An act of profound, malicious evil that did more to end the idea of neutral networks than ANY lobbying could have, and which most people still think of as totally fine. I'm also pretty sure that predated Ajit Pai.
I think this is whole question is a great example of when the industry genuinely would prefer clear rules and has been quite nervous to act absent clear rules. The unstable nature of neutral network policy at a high level meant the entire zone was a bit of a minefield, so they've been very cautious about dipping toes.