Docker was a spinoff of an internal tool used to build exactly the type of PaaS you're describing. It was like a better Heroku and I loved it, but they shut it down when they focused on commercializing Docker itself.
That was always weird to me they opted for freemium cli instead of enterprise paas play. Maybe it was just too early
My guess is the margins were really bad for a PaaS. It's expensive to build on top of other people's clouds.
There's also the issue that building an effective enterprise sales organisation is a whole Thing and if you believe you can achieve profitability via a different path then the temptation to file the enterprise approach under "I have no idea how to do this and also I would rather not" is probably pretty strong.
(this is in no way a comment about what the right decision would have been, only musing on an additional reason the decision might have gone the way it did)