Random curiosity regarding common files

With the move towards common files for several purposes (GTK, Java, etc), I wonder how these are going to be kept up to date in the future? Gaim, for example, requires a much more recent version of GTK than it did in previous incarnations. So if using a common files folder becomes fairly standard as a space saving technique, will the programs that use them still come with them in their own folder? Or will it be neccesarry to install required files seperately? Or, (last or, I swear), will there be a successor to the .paf format by then which can update both the program in question and any common files it needs? I ask all these questions because, while common files will doubtless provide a significant saving in space, it seems that they bring various additional file management problems, and I'm keen to know if a solution is planned for this.

PS - please forgive bad spelling and/or grammer - it's almost 2am as I type this