It's nice that you think all this stuff. The reality is that the technical side of SMTP service is the easy part (hasn't changed a hell of a lot in the last 20 years, anyhow) and the political side is a real burden (and it shifts with the wind).

You're not just setting up mail, you're dealing with an email cartel that does not have any desire for small players to exist. Note that I said "small players", not "spammers". Enough spam makes it to its destination that there are certainly palms being greased.