In many countries, running an exit node is a very fast way to have cop knocking at your door and seizing all your stuff. To run a tor exit node, you either have to try your best to stay anonymous, preferably be based in a country who don't care at all about cyber crime, and run them on a dodgy hosting provider who dgaf. Or you have to create a legal entity, either a non-profit or a company, depending on the country register as a hosting provider (so that you are not consider legally responsible for what comes out of your server if you abide by some rules), and you will still have to respond pretty fast to any police inquiry.

If anything, it's a miracle that there is 3000 of them. Although you can safely assume that a good portion of them (if not the majority) are operated by state intelligence services, cybersecurity companies and bad actor, who will log everything that pass through their node (and might be able to decrypt them one day).