Comment by jcgl
Maybe to some degree that's true. But let's take an example: GNOME is the only (afaik) desktop that requires client-side decorations. They've been like that for years, but nobody else is following them on that. Yes, the toolkits and a number of toolkit-less apps have added support for them. But it's not like they were actually able to employ their gravity to change the world over to CSD (thank goodness).
I don't think GP claimed that everyone copied everything about Gnome, just that every toolkit/program has to implement Gnomes way of doing things even if they continue to support others so you have that as a common (but often bad) interface. CSD is a good example of that - implementations of it have reached libraries like SDL that would rather not care about the desktop user interface at all but because of Gnome they have to.