How do you do a hostile takeover of a private company?
The Mafia does that all the time. Not sure Microsoft would risk that, but there’s an option.
Also, if Gabe doesn’t have 51% of the shares, Microsoft could buy those shares from the other shareholders just like with a publicly traded company, it’s just more difficult because there isn’t an open market for it. If Microsoft gets a 51% stake, they legally own the company at that point.