Yes, it is better. The reason is that when every email operator is small, the overall email community can pressure them to go fix things. You start by sending notes to postmaster@... with problem reports. If things go ignored you start blocking them and then they wake up fast.

In today's world when microsoft or gmail or yahoo start misbehaving in email handling, what are you going to do? It is impossible to reach them and while you could block them, they will never notice and you're only hurting yourself.

It is the classic problem of centralized power which hurts everyone except the (near-)monopolists.