Surprised no one else mentioned this... the answer is negative many months (or years?), most are Mastodon instances and probably not many people are familiar with most of those instances tho.

There was a fairly serious controversy months back when mastodon.cloud was purchased (if I remember correctly) by the same company that owns pawoo.net and another large Japanese Mastodon instance, the company is for-profit. Several right-wing shithole instances obviously have ads and are for-profit. Also there are a few instances owned/operated by for-profit companies, Medium immediately comes to the top of my mind.

Problem is a fairly significant portion of Mastodon admins I know were so staunchly against anything touching for-profit companies within a 12-ft stick that they immediately defederated from all of the said for-profit company affiliated instances...

To answer the second question... I don't know. Again, the larger Mastodon instances (over 10,000 users each) I'm aware of seem to do just fine on user donations now, but the concept of profit comes every now and then. Paid moderators/admins was also something to keep in mind for this topic.

Ask yourself these questions..

How long until http protocol is monetized?

How long until POP, IMAP and SMTP (collectively referred to as 'email') is monetized?

How long before torrents are monetized?

The answer is, quite nearly from the start you could .. but anyone can still do everything you could with those protocols by themselves, for free, without any strings. Still people monetized all those things early.

Because those are all just protocol, or a digitized agreement on rules of communicating fixed sets of information. Sets like an email, or a website, or a collection of files. No one owns any of these rules they just exist and any two computers can agree on them and use that to exchange information.

Fediverse is a protocol. Lemmy, kbin, mastodon, and the others are all just programs talking the same protocols. No one allowed any of them to do so, they just agreed to. All the entities that make up the fediverse agreed to the same thing, so all of them can talk to each other, in theory. In practice each one can choose which others it wants to talk to. Just like you can build an email client that just will not send emails to Gmail. It's not because it can't but because it doesn't want to.

As someone who also doesn't fully understand stuff yet, best comparison I've seen is email.

I'm sure there are emails that cost money, but for the most part you can just. Move to a different email. If a group is on a server that's asking for money they can just change to another server, right?