There is not only an app store concept that is being developed, but also a sandboxing mechanism for better safety when you run your apps. On top of that, you should be able to use apps that have older libraries and so forth using a system that Lennart Poettering has come up with. Again though, we do have to change Unix cultural for some of these things.
Right now, we need to continually upgrade ourselves otherwise, it will be Android that wlll be the desktop of choice on Linux machines. In fact, even the identifier 'Linux' will be gone, nobody will even know that they are running Linux since FSF can't seem to come up with something better than 'GNU/Linux". *sigh*
UNIX was not designed to stop you from doing stupid things, because that would also stop you from doing clever things. -- Doug Gwyn