Right now it seems to be the main driver indeed. If the 'store of value' Bitcoin fails, I guess in the short term, all crypto's will crash. And then the question will be if one has a decent enough value proposition to rise up again. Although a lot of people are opinionated on this last part, the fact remains that none of us really knows.

Another option is of course that one crypto would just overtake Bitcoin. If I remember correctly this almost happend with Ethereum and was called the flippening. This scenario would be better for crypto of course than a real Bitcoin crash.