That's mostly true, but even if every single one of the creators I followed were also on platform X, there's also all the instrumentation around Youtube, such a

That's mostly true, but even if every single one of the creators I followed were also on platform X, there's also all the instrumentation around Youtube, such as TV apps, Chromecast support, third party support from other sites, etc. The site itself has so many features that people take for granted until one of gone. Hell just removing a tiny portion of one feature (user submitted subtitles) had a huge uproar from the community. Most of these alternatives on the other hand don't have 80% of the features Youtube does.