Silly thought experiment
Let's imagine that instead of cutting off a chunk of Microsoft people, we just cut Microsoft into 3 (or even 5) equal pieces. Each new baby Microsoft would get a copy of all of the source code, and they could have a draft to divvy up the staff and the facilities. Shareholders would get new shares in the baby companies.
Now each baby Microsoft competes against the others. One baby might decide to go back to XP, and I might well switch my loyalties to that brand of Microsoft. Two of the others might stick with Windows 7 and 8 for a while, but one might focus on fixing the security problems at a slightly higher market price. Meanwhile, the last two might put their priorities on flavors of Windows 9.
The bottom line is that we would get some real choice (AKA freedom), and I bet the OSes would actually evolve much faster. Some employees would still get burned, but that's happening anyway.
Even the shareholders would benefit from the overall acceleration of the software industry. Yeah, one or two of the babies may do less well, but the whole pie of all the babies will be growing bigger. The only way for a shareholder to lose would be to sell the buy and sell the wrong shares, exactly like now.
Ditto Google and Apple, if you ask me. Any company that starts restricting choice too much should be rewarded by strongly encouraged reproduction, not penalized by temporary cancerous growth.