Come up with something better is the exact right response. Essentially at the moment there is a pretty stark choice between decentralization and performance / efficiency. 

You can get performance and efficiency by aggregating and thus centralizing data. That's Twitter. 

Or you can have the basic nostr model of data spread far and wide under no point sources of control with the trade-off that it's never going to have the efficiency of a monolithic database and the need to invent new optimizations that make it work acceptably well. 

The gossip / outbox model seems like the current best basic optimization that retains real decentralization (without which nostr is absolutely nothing interesting at all) and lets clients find stuff.

Come up with something better.