What will be the end game for bitcoin?

Businesses will continue to experiment with the blockchain, proving that that innovation is separable from the bitcoin the currency. At the same time, there's all these people out there who bought into bitcoin as a tinker toy, thinking they might make some money on it. Maybe they bought $100 when it was worth $10 bucks a coin, and now they're sitting on $4,000. Many of them will treat themselves to a vacation or a new computer with their bitcoins, and they don't buy back in. There's no evidence that people who spend down their wallets buy back in. Little by little it will just atrophy, because nobody is really using it. The big kids will get out, and the little guy sitting on one, two, or, sadly, many more bitcoins will lose it all.