I think this is somewhat mitigated with Microsoft these days because of their motivations for buying GitHub. For them this endeavour seems to be focused on winning developers hearts and minds rather than seeing how much profit they can make from it. Clearly they have a business case for this, but it seems more to be more geared towards making azure more and more profitable instead.
I'm not as sure as you are. Sure, as it seems today, Microsoft wants developers to be as happy as possible. But in the end, Microsoft is not running a non-profit. They are running a for-profit company and the motive is simple: earn a profit.
Today, they can afford not earning as much on their new Package Manager as they earn money elsewhere. But that's no guarantee they will act the same way tomorrow.
We've seen Microsoft go back and forth in the developers minds, and I'm sure we will see more movements back and forth in the future. Right now, things are good though.
I think it's good to be cautiously optimistic. Microsoft has a massive revenue source in Azure, and losing 100 million on Github to make 1 billion in Azure is... a no brainer.
No brainer for who? Feels like the users are the ones loosing here.
If a company is running two divisions, one that doesn't make any profit and another where they make a massive profit, which one will they focus on? If shit hits the fan, which one gets cut first?
Having some core infrastructure like a package registry be the loosing option in that case, does not feel like a no brainer when you're a user choosing a service.