It costs $34 a month for an experiment. It doesn't cost anywhere near that for a node that is running, used by thousands/millions of people, ingesting millions of pdses. Don't be misled by a nice experiment. You need servers, backups, people to run that. See what real world deployment looks like: a little bit under 100k a year for the only independent full stack.

There's no need to self host as there's already public third party instances you can switch to.

Yes it's possible. It's just not the default. That's the issue

it's not something the fediverse is immune to either.

true, although no one said the contrary

This is just incorrect. RSS is probably one of the least centralised protocols right now, it's not even federated, which makes me question why the author even included it as an example

The argument isn't whether something exists, it's what people use: rss is amazing but it's far from being mainstream. The default path to following isn't rss, which is the point (and the problem).

It's not an argument against federation. It's an argument to look beyond the niceness of a tech.