I'd love to see this backed up by sources. I for one recall seeing streaming stats from Disney+ and old series like X Files are up there as some of the most streamed.
Anecdotally, I watch and rewatch a lot of old series. Like I'm rewatching Breaking Bad on Netflix right now.
This doesn't contradict OP—Disney's new content is mostly bad, so it's unsurprising that on their platform people are watching older stuff. But would that have been true of Netflix before everything fragmented? And how many people aren't on Disney+ at all because they'd prefer to see new, good content and already finished what little Disney is putting out?
https://www.netflix.com/tudum/top10/tv
Top 10 is pretty dynamic. Longest item there was there for 6 weeks and is new content. Hilariously "Fireplace 4K: Crackling Birchwood from Fireplace for Your Home" beats out Squid Game.