I think facebook haven't used their huge cash reserves wisely which is why faltering in a single area (aka. advertising) puts them in a very precarious position.
What has google done (just off the top of my head)?
android, gmail, google maps, search, self-driving cars, glass, hardware (I know the nexus/q are manu. by asus but google do have their name on it)
What has facebook done?
facebook.com, facebook app for mobile? thrift?