Why would they? Wouldn't outbox make it easier? Yes, they may need a proxy relay still but my understanding of outbox is that the goal is that people post to the relays of their followers / people they follow. So wouldn't that mean more chinese relays get fueled with content? And if not they'd still be able to connect to their proxy relay. Most people have really big relays so those will keep getting fueled.
Discussion
In simple terms, the outbox model works by posting your own events to your outbox relays and events that mention others to their inbox relays. So when you want to fetch a user’s events, you have to go to their outbox relays.
Now, imagine I follow a European user whose outbox/inbox relays I can’t connect to—how would I find their events or mention them? This is exactly the issue the outbox model faces under China’s network environment.
this is why relays should include aggregators, and the aggregators can dynamically work around blocks by always looking for more relays to search. my relay includes an aggregator with the first "follows" based whitelist mode, and the "seconddegree" mode i will make extends that to searching for follows follows and both whitelisting the users and subscribing for their events.
if all relays did this, it would defeat the great firewall because people could spin up new relays and aggregate content and bypass their whack-a-mole blacklist system. china firewall can't be a whitelist system, because it would impede business too much, so this would be an effective countermeasure.