It's pretty clear at this point that Google's bigness is holding it back.
Milking money from ads is all they can do. Innovation is very hard when everything has to go through many layers of approvals and there are constant re-orgs. People are fighting over small slices of the pie, rather than growing the pie.
If the ad money stops rolling in, Google is done.
Smaller, more agile companies are usually where innovation comes from. Google accomplished most of the good things it did when it was small.