That is your perception. Maybe you weren't around for Compuserve, AOL, and similar attempts at walled garden networks that fortunately crumbled largely because there was an open Internet.
A better way to look at it is that a lot of good happened with net neutrality. Both before and after the regulations. Before, because we effectively had net neutrality already without the regulations, as I'll expand on more below.
The Internet thrived, and the blossoming of the entire world of web content happened.
Small startups had the opportunity to expose new innovative services to customers and markets that they might have otherwise been locked out of due to entrenched big companies feeling threatened.
The creative explosion of stuff that ensued has been fantastic.
Not all of it is good, of course, but it's hard to deny that overall it's way better than what we would have had in a walled garden world.
Some of this happened before net neutrality regulations, but in an era that had a kind of defacto net neutrality simply because the stodgy old companies hadn't yet figured out how to get their grasp around the Internet. So when thinking about this it's useful to look past just the era of actual on-paper regulation to the previous era of defacto openness of the Internet. The regulations were about preserving openness which already existed, but which was threatened by greedy corporate interests as they increasingly gained clues about how to lock things down and stifle competition.
Why can't we go back to having net neutrality without regulations? Because as I said big corporate players have now figured out how to exploit the system to the point where they would quickly threaten the openness of the net. Not that they can succeed in doing it 100%... the internet is self-healing to an extent... but without the net neutrality regulations being in place, they can choke off more of it, which would be bad.
To paraphrase, (as I understand it):
The FCC did have some rules about Net Neutrality (The FCC Open Internet Order for example), but they were struck down as a result of Verizon Communications Inc. v. FCC. To ensure the same protections, the FCC then reclassified Broadband as a utility. Pai's new rules would roll regulation will cause neither Title I nor Title II to apply to broadband carriers, entering us into new territory.