The Fediverse - especially the microblogging side of it - has deep issues when it comes to environmental sustainability.
And the high resource requirements, which result from an incredible level of redundancy, aren’t just bad environmentally: they make running a server more costly, and increase our reliance on Big Tech’s infrastructure.
I wrote about all this, along with some suggestions for how we can improve things somewhat.
Also the software needs to be efficient. Use less RAM and CPU cycles. And I don’t think the ActivityPub protocol in itself is very efficient. I’d like those aspects compared to an old federated technology like NNTP or email.
But I’d agree on the things in top. Content should get compressed and cached on demand. Neither transferred every time from the original instance, nor transferred without a user ever viewing it. Caching on demand or a DHT (P2P) storage backend could do that.