That is the simplest terms, people should realize that it's all about buying and selling, nothing more. If the market is willing to buy more and more then we are going to see it do very well, if the market just wants to sell and get rid of then we are going to see it do terribly. That has been the way any market has worked for a long time.
Even for simplest things, like let's say tomatos, if in a single season tomatos are not sold very well and people are not buying it for some reason, the price of tomato will fall just to sell it before it goes bad, but if people are buying it a lot, there will be less left and the price would go up. That's how it all works and I believe that should be the same thing with bitcoin as well.
And you are right, it took a lot of time for people to figure out the law of supply and demand but once we did so we made progress in understanding how the economy works, most of the time people try to find some kind of fundamental news to explain the movements of bitcoin, however there have been many instances in which negative or positive news produce no effect on the market, this tell us most events are not really that important and do not move the markets, what moves the markets is the demand for bitcoin and its supply and nothing more.