Fair point. But only a small minority of back end as a service users are comfortable with self hosting something like Parse.
Enterprises really like having someone to sue when things go wrong. And indie devs who pick BaaS offerings do so in large part to avoid the hassle of self hosting.
I'm not sure if it's still valid but it's not too hard, and still much easier to maintain than dealing with AWS. I have basic AWS proficiency, but it's still good to have Heroku to not think about it.
Enterprises really like having someone to sue when things go wrong. And indie devs who pick BaaS offerings do so in large part to avoid the hassle of self hosting.