"It also doesn't seem like the internet regulatory state of pre-2015 was a disaster."

The internet regulatory state before 2015 was pretty much a disaster. The early internet was de-facto neutral with a bizarro patchwork of idiosyncratic local regulations (see the quote "the internet treats censorship as damage") and a general distaste from network operators for wide-area multicast (with good reason). Neutrality became an issue with major commercialization and particularly when internet services began to compete directly with non-internet services like TV and phones.

"As detailed in the survey below, nearly every operator places
limits on “commercial” use, sometimes including limits on Virtual
Private Networks, as well as limits on acting as a server. Why
might an operator put such a restriction on usage? Doing so
obviously makes the service less attractive to consumers who
might want to act in a commercial way, even in a fairly casual
manner.

"The simple answer is price discrimination. That this is the
case is not just intuition, but can be confirmed by company policy.
As evidence we can consider Comcast’s reply in 2001 to a user
who had complained about the ban on VPN usage on Comcast’s
network:

"Thank you for your message.
High traffic telecommuting while utilizing a VPN can
adversely affect the condition of the network while disrupting
the connection of our regular residential subscribers.

"To accommodate the needs of our customers who do
choose to operate VPN, Comcast offers the Comcast @Home
Professional product. @Home Pro is designed to meet the
needs of the ever growing population of small office/home
office customers and telecommuters that need to take
advantage of protocols such as VPN. This product will cost
$95 per month, and afford you with standards which differ from the standard residential product.

"If you’re interested in upgrading . . . ."

-- https://papers.ssrn.com/sol3/papers.cfm?abstract_id=388863 [2003]

(Other examples available from: https://en.wikipedia.org/wiki/Net_neutrality_in_the_United_S..., https://www.dailydot.com/layer8/net-neutrality-violations-hi..., and https://www.freepress.net/blog/2017/04/25/net-neutrality-vio...).

Sometimes network providers got in trouble with their restrictions. Sometimes they were changed via customer and public pressure. Sometimes the complaints went to the government, usually the FCC. Sometimes they were addressed there, sometimes they weren't. Some providers were prevented from restrictions by agreements with the FCC, some weren't. Sometimes, something you wanted to do was impeded by your ISP or an upstream provider. Sometimes you could pay more to avoid the impediment, sometimes you couldn't. Sometimes you could change providers to avoid the restrictions. Usually not, though. (Strike that; try "Essentially always not.")

Increasing competition is a dandy idea, and it was the primary argument at the time. Unfortunately, there are two ways to do it, mostly: force utility-infrastructure plant operators (the phone network, the cable TV network, whatever) to be neutral with regards to actual service providers (which sort of worked for long-distance telephone providers, I guess), or to destroy all of the streets in America by laying more cables. Again.

Competition hasn't worked before in the US, and I'm unaware of anywhere in the world where it has worked.