Any uptrend you can see in bitcoin's price history looks exactly like a textbook penny stock pump&dump.
The 2011 bubble, the two 2013 ones.
They are bubbles, not healthy sustainable uptrends.
Bitcoin looks like a mega bubble that bursted that can be divided by 3 smaller bubbles/pump&dumps, the second one ended up pumping way higher than the first one, the third one ended up pumping way higher than the second one but now retraced completely returning to the second bubble levels.
Doesn't look like something anybody in his right mind should put money in, currently. And that's ignoring the fundamentals, which are pretty bad by themselves...
Only bitcoiners consider bubble/P&D cycles as "natural behaviour and growth of a promising investment".
Have you ever seen valuations of companies pre-IPO? Like when they are still in the VC funding mode and prior to that? Looks very similar to bitcoin prior to it becoming mainstream.