Would Cloudflare/Google?
Cloudflare and Google pay ISPs for the latency they get, FWIW. If I made my own resolver service today I would not be able to compete with your ISP without forking over $$$.
Perhaps you misunderstood my original topelevel comment. If that's the case, let me try to clarify: ISPs have zero technical reasons to complain that people are using alternative resolvers. I totally see why they want to provide DNS resolvers, and that makes perfect sense. Unfortunately, part of that "want" is so they can sell DNS query data to third parties, which is just another reason why I don't want to use them.
I think the main reason for this is even if your competitor grew like a weed, it would be a decade or two before you had the scale to justify rolling out a CDN/caching infrastructure like that of cloudflare. That's not a matter of simply paying ISPs money.
My issue with this is that I've never been with an ISP that had a faster response time than Cloudflare/Google - and one would think they should, after all, my ISP should be able to reach me as quickly (or quicker) than any other corporation.
My current ISP has the fastest DNS benchmarks I've seen, and they're at 81ms for an uncached response, vs Cloudflare's 63ms and Google's 69ms. Cached response is similar (since I have a local cache).
In addition, my ISP does not provide DoH/DNSCrypt/DNSSec. None. Just 'vanilla' DNS. Furthermore, they also don't provide an unaltered DNS service: they block some websites from resolving, the list isn't made available, and is decided via extrajudicial means. You cannot opt-out, and all ISPs in the country adhere to this. They're not forced by law to do so. I'm also not in a normally thought of as a repressive country: it's a member state of the European Union, after all.
There are very good reasons for people to be outright hostile to ISPs and their shady underhanded practices, as you're seeing in this discussion. I feel that it is in any mostly online-based organisation's best interests to expose those practices.