It depends. Are the current buyers mere momentum investors chasing a rising price? Or are they people who understand the merits of BTC and expect that it could ultimately be a similar asset class as gold with a similar valuation (in which case each BTC would have to have a much larger valuation than at present)? If the former, yeah we could have a big crash. If the latter, then buyers are averaging in and willing to wait for the ultimate valuation to be reached. So I'm not really on the side of either naive bulls, nor of the cynical "BTC is a fad" haters. I tend to think more people are not mere momentum chasers because everyone can see the chart with the speculative blow off in 2011 and subsequent crash. I don't think it's a valueless fad, or it never would have bottomed out. It would have been a zero already.