They literally couldn’t pay the devs. Netflix for instance flat out refused to have blackberry pay for 2 full time devs to maintain an app.
Netflix looked at the market share and determined that there was 0 benefit. The people that were on blackberry devices already had a Netflix account.
Additionally Blackberry store apps were compelling for devs. Dev feedback included ease of development and more importantly they made a lot more money on the blackberry store than on iOS/android, both because the cut was better and they could jack the prices up because the customers were not nearly as frugal.
To get into mobile would require a massive overhaul of windows apps to get them mobile-friendly
Oh look, that’s exactly what they did and now we have PWAs for lots of apps. Maybe MS is getting ready to take a stab at mobile again.
I’m ok with YouTube. I pay for a large music service and get no YouTube ads.
Every other service has only made things worse. Netflix has done the least by not yet pushing ads.