@Kowlin Eh, the way I see it, email and other assorted protocols were developed back when there were no other protocols or similar services to build off of, so it was really just the wild west.
Also, it seems everybody trusted one another and nobody expected spam to even exist, so it was never conditioned for, so now we have all of these bolt-on things you have to do to make sure your mail isn't sent straight to the spam bin... SPF records, DKIM signing, etc...
It's a miracle email actually still works the way it does.