I said somewhat the opposite of what you're saying (not exactly the opposite, because I don't believe "power users" vs. "new users" is the correct way to understand potential audiences).
Within _existing_ Linux and GNOME users, in my view there's a substantial divide about the Linux user interface. Most fights about desktops have been _within_ the existing userbase. I elaborated more in some other comment earlier.
I don't agree with blaming changes on "massive untapped market." When complaining, people like to claim that "most existing Linux users" are on their side. For GNOME 1->2, I think we have enough history to say that those people were flat wrong; GNOME 2 was dominant and successful without reaching any massive untapped market. Instead, it became popular with "most" (at least "many") existing Linux users.
GNOME 3 remains to be seen, but I think it's worth noting that the similar contemporary claims about GNOME 1->2 turned out to be wrong.
It's very dangerous for any of us to over-extrapolate from our own experience.