Personally, what I dislike in the decline of PC gaming is not that I won't be able to play the games I like on the PC, but the fact that consoles aren't open platforms. What a bulk of PC gaming for me is that I can basically the fact that I can make mods for games I like (e.g. Oblivion is a splendid example of this) and that starting up to make your own game just requires a PC. Of course, playing what other players have made is also part of the whole appeal.
What I see as unfortunate is that with closed platforms, any people wanting to make games for a device will be at the mercy of the hardware manufacturers to be able to do such stuff.
What will happen to custom player content of the future? Creator's Club is one step towards that, but I'm not seeing why I should be paying Microsoft for something they might end up selling.