I don't know where this comes from, other than fan speculations. Really. We've watched closely everything WW has released about RL, since it's our preferred setting.
Once, a while ago, the developers said the sales of the RL Gazetteers in particular were disappointing.
But when the license end announcement came, there were no comments of that sort about sales or licence price, as far as I know. WW sent out the same laconic announcement as Dragonlance's (I think not saying anything is part of the license

)
But if you have a link saying otherwise, I'd be very interested to read it.
Joël