It's almost like they continue to add nothing of value on purpose because it's admission they screwed up - they should have a tablet with macOS by now, including this feature.
In this case, revenue = device sales = popularity.
So you may think that you know more about product management and how to sell devices than Apple but given their experience it's a pretty tall claim.
Because freedom and power comes with tradeoffs. And many of those tradeoffs which come from multiple app stores, code execution etc are pretty unpalatable to most people.