I would like to think that there will be maintained Linux distributions out there that we currently have today that do not use or depend on such closed "app stores". I think we will not have to worry about this dystopian future just yet as there are like-minded people out there working on Linux distributions and do the packaging for them to keep the repositories up-to-date, and so forth. If something were to happen to Linux itself (quite possible given recent developments), then someone might just fork (I am not a lawyer, so I am not sure about the legalities). We will see. I certainly hope that it will retain its philosophy; "closed app stores" are definitely not it. :/