There are open standards for browsers to communicate with software deployed in web 3, regardless of what an isp would care about doing. For an ISP to fiddle with that goes far beyond sneaking around net neutrality as a principle. It would entail blatant violations of existing laws. In broad daylight.
Not to mention it would accelerate the adoption of Starlink and other alternatives, as well as community-deployed mesh networks that are already covering cities in the United States of America as we speak. And this hardware will get cheaper and better with time and be deployed at larger and larger scales.
It is not in any way illegal for an ISP to block or throttle access to a certain hostname or IP it doesn't like, now that Net Neutrality is dead in the USA.
Also, there is no reason to think that Starlink (even if it could ever hope to have the capacity to compete with broadband and fiber at the national level, which it can't) wouldn't also become censorius. Musk is notoriously censorius of any competitor or detractor, so all it takes is him souring on Web 3 for it to become banned from Starlink. ATT and others at least care more about the money than any personal grudges of their CEOs.
Not to mention it would accelerate the adoption of Starlink and other alternatives, as well as community-deployed mesh networks that are already covering cities in the United States of America as we speak. And this hardware will get cheaper and better with time and be deployed at larger and larger scales.