| Card games have always been popular as they're relatively easy to design and manufacture.
Expansions have always been popular as they're a relatively easy way to generate more money from a well-received game.
I don't think there's anything particularly new or interesting about that trend.
You might be interested to know that FFG's trying something they're calling "Living Card Games." They've got two right now, A Game of Thrones and Call of Cthulhu, both of which are just repackages of the respective CCGs. The idea is that an LCG is basically a non-randomized CCG, where you buy a core set that's got everything a couple people need to build decks (and actually build real decks, not just throw a bunch of random cards together).
I definitely don't consider either RFTG or Dominion to be breaking any molds, at least business model-wise.
Tangentially, I can't wait for the Dominion expansions, but I have absolutely no interest in RFTG's expansions. I like the idea of RFTG as a single, closed game. | 
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