I mean...obviously the current system is not going to work as well as it would with better cameras and a better processor. Tesla wouldn't spend the money on better cameras and a better processor if there wasn't going to be an improvement. With 4x the pixels on the new cameras, they should be able to see details twice as far away, which would be nice because I always feel like my car isn't seeing things soon enough.
Who knows what Tesla will do for their current FSD owners. My car got one hardware upgrade already when they updated the FSD hardware, but Tesla's customer service has really been going further and further down the tubes every year, so I'd be surprised if they keep updating these cars indefinitely. They did promise that they would keep upgrading hardware until FSD was attainable, but they've broken promises to customers many times.