Satoshi no longer has access to being a core dev, and it's written in to the blockchain that 21 million is the supply cap. I hate this man with a passion, and trust me I know hate is a very strong word.
Like, seriously, isn't this funny? Although I don't take Jamie Dimon as a serious person when it comes to taking people's opinion as far as Bitcoin is concerned or even the future of Bitcoin, really.
Secondly, it is great to know that Bitcoin is an open-source technology and what that means is virtually all the users of Bitcoin have a control, in a way, over how it operates and nobody has a control over the future of Bitcoin because it's a people oriented platform. So, let's even assume today Satoshi Nakamoto is to come into limelight. I don't think he has a strong opinion or any strong effect on the development of Bitcoin and there are no any back-door control room in Bitcoin. If there was something like a control room for Bitcoin, people with more knowledge about the Devs of Bitcoin must have mentioned such a thing.
Lastly, the 21 million BTC cap. It's not even going to happen now, so why worry about it in the 1st place? For me it doesn't make any sense, rather it's coming out from a pessimist like Jamie Dimon. Laughs.