I just renewed bitcoin.org and bitcointalk.org all the way up to 2029.

This whole thing backfired badly on Ethos Capital. Not only have they caused a PR nightmare for themselves and raised questions around corruption at ICANN, they've also made their intentions so obvious that many .org domains have already renewed up to the maximum limit preemptively, limiting the revenue Ethos can extract in the future.

Always been curious about the power of these registry operators though. Suppose Verisign one day went crazy and suspended Google.com or refused service, can they even do that? Or just simply refused to allow Google to renew the domain and then took it for themselves?

There will be a big push to move away from ICANN eventually, and more towards alternatives to DNS, but if those alternatives end up controlled by a consortium of companies like Google, Facebook, Apple, etc, it'll just mean these companies will own the internet. They already de-platform certain people, imagine if they can make your site completely disappear from DNS and search engines and social media.

A blockchain solution is unlikely to work here either, it would remove trust and centralized points of failure, but would come with the cost of having to know how to secure your keys which most users aren't interested in doing.