It's easy to complain about this. But let's also keep in mind BOTH (1) That erecting a billion-plus actual legit revenue business is NOT easy. (2) That network effects can often amplify such businesses - but that this is not a new issue: remember "nobody gets fired for going with IBM" from way back. (3) That these unstoppable giants DO actually have a short lifetime: remember AOL, myspace, Sony consumer electronics, Yahoo, DEC, HP, GE, oh right IBM, and so many others, in fact most others.
So that one problem is looking at all this with a too short timeframe. In fact, NONE of these are sure bets or guaranteed ANY future. They have to keep performing. They have to keep avoiding fuckups. They will still not avoid better run, or more lucky competitors.