Things started souring in 2008 right? That gives me 4 years of runway, for my btc to reach the moon. With this growth rate, I'm ok with that.
Therefore, I do agree that the stock market is in a bubble -- in that sense the USD is in a bubble. It's not going to burst anytime soon, but do yourself a favor and hedge your bets... pick up some bitcoin so you've got a stake in the new economy when your value in the existing one crashes (you don't have to buy an entire coin).
But, with bitcoin's limited supply and increasing demand, and it's purchasing not being limited by credit availability (like housing, cars, etc) then chances are good it's demand will continue to increase and therefore its value will continue to increase.
If that doesn't happen then that means bitcoin's design is flawed -- it was literally designed to go up in value over time because it was invented out of frustration with fiat currency that nearly always goes down in value over time (inflation). The blockchain isn't the only brilliant thing about bitcoin.
A bubble getting bigger is still a bubble.