It was below 1k last year beginning. But from the mid year prices started to explode! What's the reason behind these price rise?
Bitcoin has high price because the demand for it is very high. Normally for anything which has high demand has high price. Not only the demand, the popularity, technology and usage drives this crypto price higher and higher every day. As you said Bitcoin price is high but as of now the price is low compared to the last year high price it achieved.
Absolutely, everything in the market regarding the value is basically centered on demand and supply. Last year, demand got so huge and people took it fast to start loading up for the next way to the moon and that was absolutely all that happened. It is a normal thing for a decentralized market anyway, with respect to the fact that no one controls it, but that can give room for manipulations by whales.
OP's is this really supposed to be a question for debate? We already know how people got so greedy and switched into the FOMO mode last year with bitcoin increasing and increasing nonstop and almost even got past the moon. The demand increased, we had a huge pump as some believe it was as a result of a high level of manipulation, but at the same time, it is really nothing much as we are here now correcting from it.