I deleted my old Disqus profile this morning. I'd created it back when I was still on Tumblr, because that place didn't support discussion on a post. But it was always a hassle to use, particularly on mobile devices. Then I discovered that Disqus was inserting advertising and tracking, and stopped using it altogether.
I do use WordPress.com for some commenting, although of course that's limited to sites that a) run on WordPress, b) are connected to WordPress.com. Thankfully, it is now possible to close your WordPress.com account—sadly, I had to abandon two accounts tied to previous (now disposed) email addresses because of that barrier.
Since I'm no longer on any of the major social networks, I take a dim view of sites that require one of those in order to comment. (Assuming I see the comment section at all—due to content blockers, that's not often the case.) As for those sites that have removed the ability to comment on their site, and suggest that you go to their Facebook page if you want to comment... yeah, looking at you Macworld!
OAuth was supposed to solve this. Maybe IndieAuth can succeed? I certainly hope so.