I assume you are referring to a physical copy of the Sega CD. As long as you still own a Sega CD you can play physical copies of games. Recently PlayStation closed down their online service for PS3 so you cannot access any digital games you may own even if you still have a PS3.
It feels as though we are moving back towards cable with all the different services and none of them are really anything to brag about anymore. I canceled my Netflix when they raised the prices and stated they would end password sharing. I then canceled my HBOMax when they started pulling content I liked to watch and I had already previously canceled my Hulu account since they really didn’t have anything worth watching. Now I am down to Amazon, Paramount+ (as it is free with WalMart+), and Crunchyroll and I rather like have less choices as it gives me the push to go do something else besides watch TV.