The arguments against net neutrality often focus on crappy connections; on 3G networks and early DSL it was common to have rate limits, which made people be very careful with how much internet they used, and/or additional fees above a certain bandwidth usage - similar to utilities like electricity and water (although IDK why there was never really much pay-per-megabyte internet, usually it's a flat fee).

The arguments against net neutrality are related to that; instead of limiting how much people use to keep the pipes open and fast enough so to speak, it's giving certain services preferential treatment, so that in the case of limited bandwidth those aren't disrupted.

Of course, it's a silly thing; most landlines, especially in the cities, will have fiber connections at least up until a local distributor box, and in some cases to the door. This has many gigabits of capacity, which should be enough for everyone.

The thing is that apparently, investments in bandwidth aren't being done enough. Google gave it a good try with their fiber service, but had to give up - probably underestimating how expensive it is, or they were blocked by the existing ISPs that didn't tolerate competition.

TL;DR, I think the problem isn't available bandwidth or whatever, it's competition, or the lack thereof, and investments, or the lack thereof.