Nothing around us will last forever. The computer I'm using now will only last a few years, but I'm confident BTC will last many more decades. Even if the network's going down to 2 computers, BTC can keep on going. The real question is how many people will keep on using it. I hope it will grow, and each time I'm watching the news, I see reasons to be hopeful. I see larger and larger deficits in most countries. I see more and more taxes to try to curb those deficits. I see more and more civil unrest, the yellow vests people in France, the occupy people in the US... Sooner or later, people will realize that BTC is a safe way to keep your savings, and to do business outside of the eyes of the devil, the taxman.