the system doesn't need to be completely pull-based though. I don't even think most modern RSS readers are fully pull-based, don't they support WebSub?

the main point is to separate publishing and distribution, making publishing far more accessible and decentralised. for that to happen, I guess, from a publisher's point of view, the system should be pull based. of course we can have hubs and relays to add pull-based mechanisms to ease the load of the system.

p.s. even in that case, strictly speaking, yes a pull-based system, or even a hybrid one, will always require more work than a fully push-based system.