Google’s “20% time,” which brought you Gmail and AdSense, is now as good as dead

It probably made more sense to have 20% time when Google didn't have tens of thousands of engineers. When you have a few hundred really smart people all working in the same building back in the early 2000's in Mountain View, it was I imagine a different thing than it would be now.

I think there may be some truth to this. With a company as large as Google, it may no longer be as beneficial to give everyone 20% time. Instead it's better to take the best engineers (and probably most innovative) and give them 100% time in Google X.