I wouldn't worry about Eberron too much on this front. Look at it this way, with one of two outcomes:
1) Eberron is a flop on the PC Gaming front. Forgotten Realms, a known winner, returns to the fore, and the next gen of games are once again set in FR.
2) Eberron turns out to be a surprisingly good game setting, and we see some original games that challenge us and keep us entertained.
Either way, we get a good setting out of it. WoTC won't push Eberron if after a period of time it is proven that it doesn't have a sustainable audience. They aren't foolish. But do expect Eberron to be leveraged heavily for the rest of this year and part of next. I know poor Hellcow (Keith Baker) is hoping we'll like it, because of all the hard work he and James Wyatt and others have been putting into it, but he's a realist too, and based on previous work can separate good from bad; if the audience rejects the setting, they'll find out in short order.
