Some years ago the price of Bitcoin could be well predicted ...... it has become very difficult for major players to predict the price of Bitcoin.
I disagree.
the ability to predict bitcoin has not changed whatsoever. if anything it is becoming increasingly simple to predict it as time goes by and the market grows. the rise and the way it happened doesn't change anything. speculation is not something you do once and be done with it because that is the correct one. no. things change and with it the speculation changes too. we never had the mass adoption of Japan before 2017, it happened so price went up fast and big. and a lot of other things.
none of these means price is manipulated just because your initial speculation 2 years ago were wrong. it just means you forgot to adjust.
1, They control huge volume of Bitcoin in daily exchange
2, They set the major Limit and Stop orders in Bitcoin price hence they set the Bid and the Ask.
they keyword in your comment is "THEY". so unless you think 20 different bitcoin exchanges are secretly cooperating together to manipulate the price, then you are wrong.