Mostly because ICANN is just a small part of the centralization of domain names. But yes, we talk about it all the time. :)

OpenNic is not that much better. It is also centralized. It's just different overlords.

It's like the PlayStore vs F-Droid. Both are centralized catalogs with their own review process to what and who can be there. Exchanging one for another doesn't solve much.