First of all let's loot at the possibility for that, this is something that had already been programmed to only exist under the limit of 21 millions bitcoin to be mined, after this, the miners will have no reason to get stranded because they will depend on transaction fees, accepting this also will mean that bitcoin doesn't have a fix supply which we have already been preaching about and that equally makes no difference with fiat with unlimited supply, having this alone could make some believed it could be manipulated and untrusted.

JP Morgan and Jamie Dimon might have only suggested this as the way they feel and not bringing it as an idea to see come through, this is more of an interrogation through the media and everyone speaking his own opinion, which could really be something entirely different from the way bitcoin is or can be, but that doesn't suggest the things we should also expect to be in the same direction on what they are thinking about, the bitcoin network was set, it's working perfectly as it has been created for and there's no more to add or deduct irrespective of the people's opinions except the developers shift ground which is likely most impossible.

I'm guessing, after years of bashing bitcoin, Dimon has at least done basic research on what Bitcoin is enough to know why the 21 million limit can never be changed. As a banker, I doubt he would hate Bitcoin so much if he didn't have a clue how it worked and how powerful it is, otherwise he would have no reason to be afraid of it and no reason to hate it.

But, being a bitcoin hater, he understands that the vast majority of people have essentially zero knowledge of how bitcoin works and so most people don't actually understand why the supply cap can't be changed, and he is trying to attack bitcoin by sowing doubt in their minds. He's hoping to turn off potential future bitcoiners by seeding lies about Bitcoin in their minds.

Satoshi created BTC, but does not control BTC; that is the beauty of the network, freedom, permissionless and censorship resistant. Satoshi didn't create the network in such a way that he could come back at any time and take an arbitrary decision, if it were created in that way, so many people would not have bothered to use BTC or have any interest in it.

Sometimes people say what they do not understand because they want to criticize, or maybe they even understand it but they just want to elicit some kind of reaction from people. I'll advise that if people want to get good information about BTC they should not listen to Jamie Dimon.

Jamie Dimon, expressed his personal opinion and that is what it is, he can not speak for the multitude of adopters that have accepted Bitcoin the way Satoshi Nakamoto, designed it, Bitcoin ETF has happened, bull run is building up in top gear, and investors are increasing, there's nothing to worry about. I believe that nothing can alter the 21million Bitcoin limit, he is a Bitcoin hater so we shouldn't expect anything good about Bitcoin from him and other critics.

Janie Dimon only knows about fiat, and thinks that because he is successful means that he knows about bitcoin technology. I wouldn't blame him for such thinking and speech because this is how the government manipulate fiat by printing more money and he has brought that thought into his head, forgetting that bitcoin has a protocol and it is design to follow such protocol. He has shown the public that he doesn't understand anything about bitcoin and that there is no back door to bitcoin manipulation. It is because of the way that bitcoin was designed that made it more valuable and impossible for anyone to change anything in its design. The nodes are programmed to to make their own decisions and all nodes decisions are the same, this makes it difficult for anyone to change anything because bitcoin network gives complete decentralization.

How dumb the crypto community is becoming to give someone with no knowledge of basics as critique of cryptocurrency.

If Satoshi came and hard fork to bring more coins off a new branch it will be just another coin not just bitcoin and people won't use that coin but why Satoshi will do that?

The fact that anyone can criticise in any way will not change anything in Bitcoin. A comment from Jamie Dimon made me wonder how he views Bitcoin. The total supply of Bitcoin is already said to be 21 million. If Satoshi Nakamoto takes any decision to increase or decrease this supply, BTC's grave will be written. It will be clear that he has been anonymous for a long time. But I consider these things to be fictional stories. Any such attempt will fail completely. Moreover, if any such action is implemented, how can we call it decentralised? I think Jamie Dimon has no basis for such words.

I would say they are making no sense with their remarks. First off, Satoshi is not coming back, and even if he did, he wouldn't come back and spoil what his creation has achieved so far by removing the limit on the supply and increasing it which would affect the value of the coin significantly, of course. Secondly, the whole cryptocurrency industry will start having doubts and lose trust in Bitcoin if something like that happens, I can't even think about it theoretically.

Satoshi created Bitcoin as a decentralized cryptocurrency that would be running on a public chain that would be controlled by miners who would use their computing power to mine blocks. He can't just come out of nowhere and make changes in the network when all the miners have been helping the blockchain work since the beginning.

It's technically possible if a consensus can be reached, but only one problem with this removal of the 21 million limit  is that Bitcoin isn't run by one man as it needs other stake holders to buy in into this idea of a fork which is likely to have a negative impact on price as this could take its value lower...
And Satoshi being a smart lad I don't think this change would benefit anyone especially that he understands the dynamics of supply and demand on price, Bitcoin is better won't any change to its total allocation...

The number of negative comments on and about Bitcoin over the years has become insanely much but Bitcoin is always coming out strong.

Considering the comment he has made, I don't see the reality of it as it is not any different from what others have said. It is also a tech and can be mirrored by fellow tech gurus, the possibility has not been seen to exist and there is no fact to back his state. I consider his statement baseless.