$18.4 billion dollars is a LOT of cash (to compare, Google raised $2.7 bn with their IPO). They can buy 18 SpaceX's, 2.3 Twitters or, you know, 18 more Instagrams. Their future is minted.
This industry is so messed up...
But nooo, say that to most people in the industry and they'll chew your head off for being narrow-minded and oblivious to how 'the economics of startups' works.