[wmf]

PDSes should be sharded not replicated. Your posts live on your PDS which lives in one place (although it can move).

[evbogue]

What's stopping us from doing both?

[wmf]

Cost and complexity tradeoffs. IMO the relay/appview is the current bottleneck.

[evbogue]

This is why I'm hoping fiatjaf has a recommendation here. I have a feeling he might have a proposal that solves this. But doesn't solve all of it, just some of it.