Whilst technically accurate, this is drawing conclusions off a very limited data set. Bitcoin doesn't go back 100 years does it? By definition this trend is not sustainable forever, so it will be broken sooner or later. It's not entirely irrational to think it will be broken sooner rather than later. Anything else is just opinion.

If we're talking opinion, I've never seen a bitcoin bubble commence whilst a majority of traders were expecting it. Right now everyone seems to be waiting for the inevitable bubble. I'm not sure it can happen until people start thinking it's not inevitable after all. BTC has a history of breaking a pattern when it has become obvious.