It disregards the benefits of a distributed platform. Imagine if the admins went rouge, or the server data was irreversibly lost, suddenly all that content would be gone or under the authoritarian rule of the admins. Bit dramatic but you get the point.

If the majority of content is on there, we've quite literally taken a decentralised system and centralised it lol

Personally, I've found Reddit now Lemmy to be better than other social media because the focus is on the content rather than the poster.

Instead of following individual people, you follow topics. This encourages more quality content rather than personal clout