Comment by marginalia_nu

The problem with having a platform like that is the obvious incentive for rent-seeking.

In the short term user interests align with platform interests because this creates a rapidly growing user base, but in the long term it's contrary to the platform's best interest to act in the users' best interest, as a large number of users alone does not translate to profit, so what happens is what's happened to Facebook, Reddit, Twitter; basically any mature social media platform still around. They turn themselves to poison.