Because it isn’t magic, there’s still Twitter auth required https://github.com/zedeus/nitter/blob/master/src/auth.nim

Every individual running their own instance would be the equivalent of every individual having their own Twitter account, which defeats the purpose.

Well, not totally. It's read only, which changes how people engage. It also lets you control ordering and presentation. It also lets you hide ads.

We need a multiplexer in front of all these instances. One that works like a load balancer, health checking the individual instances and adding/removing them from the pool automatically. That would allow people to create new accounts, serve their own instance and attach them to the muxer.