It's that age old, you get what you pay for. I recognised this long ago and have bought and run my own hosting for years. Storage is not free, data centres cost money, the land, buildings, security, fire suppression, the computers themselves and the power to run them not to mention their connection to the internet.
I am currently a resseller and can host if anyone wants an account just for email or anything else. I use a UK based company that are really good. I'd never dream of using someone else's services, not because of privacy (it's still illegal to read customers emails and if found out that is massive reputational damage not to mention possible legal action) but because I like to have choice and control. I don't have to jump through hoops to get any mail client I want to work.
Gmail seems to be the provider of choice now for spammers but I think they take the accounts down fairly quickly too.