What you’re describing is no longer federation but full P2P. From a purely technical point of view, it may work, but the biggest problem will be abuse (spam, excessive resource use, illegal content). When a new instance shows up, how do you know if it’s a spammer or not? And if an instance is blocked by another instance, whose side should you be on?

This is true. If you run the reddit-grab project directly without using the warrior (sudo docker run -d --name reddit --label=com.centurylinklabs.watchtower.enable=true --restart=unless-stopped atdr.meo.ws/archiveteam/reddit-grab --concurrent 6 yourname), you can set up to --concurrent 20, and some projects do work well with higher concurrent, but not reddit. 6 is already pushing the limit.

I’m running reddit-grab on 25 VMs on azure (trying to burn my $200 free credit that expires in 10 days) and I can only run --concurrent 4 safely on most of them. The only VMs that can run --concurrent 6 are the ones in India, which seem to be soft-ratelimited by their higher latency anyway.

I think the biggest cost will be image/video storage. The text takes very little space in today’s standards. The good thing is that symmetric fibre internet connections are becoming more common so it may be possible for members of the instance to contribute unused disk space to help with its image/video storage. This plus limiting the image/video sizes (and maybe forbidding video uploads altogether) will allow the instances to scale with user count.