Youtube's only done a good job is you use yt-dlp to download the videos. Watching on youtube the video gets interrupted multiple times for "commerical breaks".
I’ve been using Gaia gps for what feels like forever without it becoming shit.
I hate to say it, but Gmail has been solid since 2007.
I would go for Reddit if you use “old” I guess and pick good subs.
Fan/individual/community run sites and networks seem to avoid this issue, since they don't need to make a profit from their work/pay off those venture capital investments. For example, the Nintendo Independent Wiki Alliance seems pretty good there, with the likes of Mario Wiki, Zelda Wiki and Bulbapedia most relying on unintrusive advertising to stay afloat.
For a well known platform? I guess WordPress.com seems pretty good in that respect, at least from the sites I've visited there. Can't see many ads, paywalls or other dubious practices there.
Linux? stretching "consumer" platform a little here.
Costco?
Bandcamp.com