The 360 was a success for them, that's why no one was really complaining. However, at the beginning of this gen, when it became apparent that the One wasn't going to come close to the PS4, investors started making noise. Bill Gates even said he would be fine with them selling or spinning off Xbox. I remember one candidate for the CEO position was sounding that he did want to get rid of it. The current CEO decided to keep it, but also cut their funding, most likely to appease investors. I'm sure he has them convinced that they need to strike hard next gen in order to have another 360, which is why they bought a bunch of studios recently.
Unfortunately for them, Sony isn't looking to make the same mistakes as the PS3, which were the real reason 360 was able to take off. I think Sony is ready to launch next year, if they choose, but may hold off if they see no signs that MS is launching next year. In other words, MS won't really have any advantages to win next gen. Maybe a slight power advantage, but that won't be enough. Which is why I think the CEO will, yet again, cut funding to Xbox so that investors won't be up in arms about it wasting them money.