The high valuations for these companies can only be explained by the expectation that they will maintain their market-share for years to come. But the fact tha

The high valuations for these companies can only be explained by the expectation that they will maintain their market-share for years to come. But the fact that they're willing to throw so much money at buying out the competition is, to me at least, a red flag that their market position is actually fragile. When Facebook bought Instagram for a billion dollars, they weren't interested in any of Instagram's engineers, technology, or infrastructure, just in defending market-share. Other than for the bad optics, everyone at Instagram could have retired shortly after the deal for all they cared. The threat was eliminated. This isn't a sustainable practice. I can't help but feel the whole thing is a game of hot potato. Greater Fool Theory in action.