Got it, thanks for the reply!
However, I think this is one of those examples the situation has been assessed incorrectly, perhaps with an emotionally charged decision. Yes, a free Musicbee would be indeed a waste of time and resources. But given that an entire platform's userbase is literally starving for a proper player, they'd 100% gladly pay for it.
So most developers simply gave up
This is very very false. It's a known fact that developers favor Apple's ecosystem, as it's more lucrative. People who own Apple devices tend to be more financially stable, and thus that market is more willing to pay for software. It's not a coincidence that most apps are much more polished on the iOS front, compared to Android. Same for Win/Mac. (I use both).
Oh, and did I mention that most artists, musicians use a mac?
The simple answer is that Apple wants control over everything.
Frankly, every company wants as much control as they can get. Apple is just the one that succeeded with getting away with larger amount of control in comparison to other companies and platform makers.
All aside, a Patreon funding might be a viable way to collect money to cover the development costs...To me, it seems like the team is having a hard time believing that they could make money from a paid mac version of this software.