And that is the supply and demand principle in play. Definitely, when there is significant demand from the market, the price will eventually rise up because we know very well that the bitcoin's supply is fixed. So it is only a matter of when it will increase depending on the market performance.
Also, as you said, price manipulation in btc is quite hard because you need very large capital just to make a dent on its market. Therefore, hard to implement the wash trading technique in btc market. Whereas, if you talk about small cap coins, even the devs can create a sudden pump because they only need small amount of money to manipulate its market.
Bitcoin has a capitalization of over $1 trillion and accounts for 50% of the total cryptocurrency market capitalization. That is a very large number, but compared to other financial markets such as stocks with a capitalization of more than 100 trillion, gold more than 15 trillion, or even bitcoin which is smaller than the capitalization of a technology company like Apple, Nvidia...has a capitalization of more than 3 trillion. Bitcoin is still very small in the international market and manipulation is not too difficult.
Not to mention, is there any guarantee that powerful organizations such as the Fed, the government... will not participate in this game? And for them, just releasing a few pieces of news is more than enough to manipulate the market for their own profit.
I do not deny that bitcoin is based on supply and demand but it would be correct to talk about the long term, in the short term it is inevitable that there will be manipulation by some organizations. Furthermore, a market that does not have many regulations and remains unregulated would be ideal for whales because manipulation is much easier, they will not miss this opportunity.