I'd like to know if there is really someone who would possibly able to know when the market crashes.
I have pondered this until my brain almost exploded. My best result is that a rough guess is possible, but it is fundamentally impossible to predict with any precision when or at what price a bubble bursts. This is similar to volcano eruptions. Sometimes you get some advance warnings, but a precise prediction is still impossible.
Why is this so? Because a single big seller can burst the bubble by selling a large amount and perhaps another large amount just when the price attempts to recover. If there is no big sale, the bubble can inflate higher and higher.
A second effect is that buyers simply run out of money. If you look at the bitcoin price curve of the last few months, you see that we have super-exponential growth, which is impossible to sustain for long. Even exponential growth quickly becomes unsustainable.
And when you look at historic price bubbles, one conspicuous observation is that the peak is always pointed. You never see a rounded head or a "permanently high plateau". It does not necessarily have to be pointed when you look at it through a microscope, but for any normal observer a price bubble always has a pointed peak.
This seems to indicate to me that the bubble also bursts on its own when the accelerating price increase cannot be sustained any longer.
I believe that there are a few simple psychological phenomena at work in these bubbles. You know how the run-up feels—you could observe that here all the time. After the burst you get the effect that many late buyers panic and sell at a loss, relatively quickly driving down the price.
By the way, let me try to explain the stupidity of a price bubble in a different way. From the dollar point of view, bitcoin trading is a zero sum game—no dollars are created or destroyed. They only change hands. This means that necessarily there will be winners and losers. But against all rational sense almost everybody believes to be a winner. That is like asking people whether they believe to be above average car drivers; some 80% answer that they believe exactly that.