They can easily manipulate it in the price they want to.and many of the small traders will buy and see if they are  able to buy it cheaper.

If that things happen I don't think someone continue to have interest buying it ,if they know that there are whales that controling price. if that thing happen I'm sure others people or more of the investorrs will prefer to just look for  another crypto currency that is not easily manipulated.

Now, do you mean all the remaining coins left to mine, or all the coins in circulation now ?

Either way, this is a ridiculous situation, and not something that would really happen.

In the light of nonsensical, I can give an extremely nonsensical answer to show how this is not something to worry about.

Let's says the whales start buying up the last of the few remaining coins, as you put it.  This would shoot the price up to the stratosphere.  The market cap for bitcoin currently sits at over 250 billion.  Then the remaining coins that have not been bought will try to equate to that value, so one can say that this would push the price of the last bitcoin to over a billion (to keep this simple).  Maybe it hits 5 billion.  Whatever, this is nonsensical.

Now we are in a situation were there are no more coins left to buy, and then someone like me starts to sell a single bitcoin.  I'd begin by selling tiny amounts at first so that I could draw out as much value as possible.  If I am careful enough I could sell my one bitcoin for a billion dollars (since no one else is selling because all the whales are holding the last bitcoins).

OK, on the other hand, yes, please, all whales out there please buy up every last remaining bitcoin.

They have been manipulating it already but they won't do that forever as they just can't simply do it.
Bitcoin as it stays longer the adoption will increase and with the increase of adoption, the manipulation power of the whales will decrease.

Just think it this way, whales buy low and sell at a profit but the market trend will not be forever as it will change overtime especially if people will be more educated as they will make a matured decision.

Bitcoin will be successful with massive adoption, and that means we are enjoying its use case.

Yes, if the whales can spend around $248 billion, then they can own al bitcoin currently circulating in the market, which is highly unlikely to happen! Also if onsly a handful of whales own all bitcoins, there will no circulation of bitcoin within the market so bitcoin will be pretty much dead. No one would want to invest in a dead currency so bitcoin's value will become zero! So whales will not get any profit out of it, so they wouldn't do that either! Hope it makes sense!

That's my take on this situation. If only few whales will hold the remaining bitcoin, it will not create demand from the market as they are holding it. Without demand and supply in action, the market is dull and don't think that it will be valuable if there is no market movement. Right now, the market is dictated by demand and supply and whales may want to possess large btc holdings but they won't aim to get the large percentage of it.

If a few whales control all Bitcoins,the BTC market will disappear and Bitcoin will become worthless,due to the lack of market liquidity.Your hypothetical situation will never happen in real life,because the crypto whales need the army of small traders and users,in order to "exploit" them and make profits out of price manipulation and forcing the crypto newbies to sell their coins when there's panic in the crypto markets.
There are also two additional reason why the whales can't buy all Bitcoins.
1.They don't have enough capital.
2.Buying large amounts of BTC will drive the Bitcoin price to the moon,so buying more BTC will become more expensive and difficult.

There is no possibility of whales buy the left Bitcoin in the market becasue Bitcoin is in the open market where anyone can buy the said Bitcoin. Those whales can only buy some few stash in the market to influence the general market for their gains, though, the whales can't have the full control on the general market because of market demands.

Let's say they managed that, what will they do next? How long will they be able to hold it without exhausting their own capital? They will have no choice but to unload them if they want to stay liquid. The question is at what price? They can try to manipulate and pump it but that will still be decided by the market. If demand remains high, good for these hoarders. If people decides to move to another market/crypto and let BTC price tank, then disaster for them. Remember, these guys are investors and they want to take profit as much as possible.

Yes, I mean all the coins in circulation now. For example Grayscale's been buying alot from miners. Thanks for your intersting opinion.