This is a direct result of our Wall Street economy. Wall Street demands that each corporation’s stock price shall increase every quarter. No matter what. If that means the customer is unhappy or that a corporation must consume itself from within. Doesn’t matter.

Pretty simple. Stock go brrrr.

Fewer people are buying PCs now that Smartphones have replaced the need to have one for most uses, but Microsoft still has to make more money every quarter than the quarter before because the stock market doesn’t value stable profits.

It got here because it’s super profitable, and that’s all the C-suite cares about, and they’re the ones calling the shots at the end of the day.

I also think that engineering ethics has, in general, been strongly de-emphasized, and true holistic ownership of technical products is now usually held by business and finance types instead of engineers, with all the negative consequences that that entails.

Edit: also, don’t forget the Peter principle

Having control over other people’s computing gives you power over them: you can gain from their detriment. It’s not like everyone is uncaring or greedy but even people with good intentions do not have infinite willpower to resist temptation. When the user doesn’t like a change from an update their choice is usually to put up with it. Defending ads in a menu or opt-outs that should be opt-ins in hidden menus is less mental work than learning what an operating system is and that you can use a different one.

By sharing the source code instead you give up that power - if you fail to be good to the users then other devs can work on it without you.

MS doesn’t care about the desktop operating system except how can they control it like Apple and iphones. All the money is in O365 and Azure these days.