Before anyone screams at me I'm just making a point. I don't believe these graphs have much to do with the irrational exuberance behind the price. This is simply to make a point about linear growth versus exponential. Let's say that Bitcoin adoption continues at a linear pace as it has done for several years and the exponential is speculation. Now here is a 6 month linear graph. 6 months, I didn't have to go back 3 years.
It doesn't make much sense for the price to rise linearly. It's just as "hard" for a price to go from $1 to $2 as it is for it to go from $1000 to $2000--it's the same amount of growth. If you invest $100 when the price goes from $1 to $2, or if you invest $100 when the price goes from $1000 to $2000, you end up both times with $200.