I think it's a stronger phenomenon in cutting edge areas, as there's less group-think to fall back on or use as a crutch.
Everyone knew what to do with a typewriter, even if the visionary leader left. If the person who was saying that microcomputers were going to be the next big thing quit? Nobody else has that idea in their heads.
Is this from a real-world example? Because I'd expect the opposite to be true.
Cutting-edge areas tend to attract people there for the vision. And the harsh commercial realities of innovative markets mean companies get in trouble if they get complacent. Whereas people in larger, older companies in stable markets can let their vision die and just go on doing whatever worked before. At least until it doesn't work, and then they're screwed.
In this instance, Google is a larger, older company.
Or to extend the analogy, if someone goes to IBM as director for New Technology X, and then leaves five years later, what's the likelihood people in New Technology X Division are going to be able take his or her responsibilities over?
Big companies are big companies and they usually don't encourage or reward employees overly much for striking out in a brave new direction. Which is hilarious given that they'll continously try and hire exactly those people externally.
Though I suppose you honestly can't encourage too much rebellion when you make your money from a crank being turned (and happen to need 1,000 bodies to just shut up, turn the crank, and get paid).
Everyone knew what to do with a typewriter, even if the visionary leader left. If the person who was saying that microcomputers were going to be the next big thing quit? Nobody else has that idea in their heads.