Users concentrating on large servers benefits all the servers where content lives by reducing the number of connections they have to make to update data. Large user servers also act as a cache for the content, reducing storage duplication. Finally, large user servers improve the UX for the Fediverse’s biggest weakness: figuring out how to get your instance to talk to a community on another instance.
Meanwhile, the current situation is helping the developers refactor the software to scale to actual large user bases - the tens of thousands of users on Lemmy.world do not constitute a “large” user base by any internet-scale metric. It also concentrates the DDOS jerks on a target with the skills and resources to fight back. Finally, small servers going offline are a substantial burden on the instances that remain.
Big, robust, secure instances for users, smaller distributed instances with limited direct access for communities. That’s the real practical architecture for Lemmy.