The guv has already responded on this. No. Its not true. Dragonlance has a 20 million+ sold number attached to it. Salvatore has 10 million+ on his website. Which are great numbers, but not DL numbers.
First off, you haven't linked to the figures you're providing.
Second off, from what you've said, you and Morrus are not comparing like-with-like. You and Morrus are apparently comparing "All Dragonlance Novels ever" (which is what the 22+ million figure is for, from my research) to "FR Novels written by RA Salvatore".
Come off it. That's obviously a false comparison. If we compare all FR novel total sales to DL novel total sales, who do you think is going to come out ahead? Given RA Salvatore by himself apparently has moved nearly 50% as many books as the whole DL series.
Also, please note that I prefer DL fiction to FR fiction, and I think RA Salvatore is a hack when it comes to everything but fight scenes so this isn't one I want to see the FR win on. But it will win. By miles.
Perhaps more importantly, the FR is still selling, still making bestseller lists. Like, this year. 2014. I don't know when DL last made a best-seller list, I can't find any info on that, but I'm guessing it wasn't this decade, and was probably before the middle of last decade.
Further, all the whining people do about "Drizzt clones" (totally valid whining, I used to whine about it as a DM back in the day!) shows that Drizzt and his ilk are very popular. They're what people want to play. I will also say this - I've never seen a "angsty" Drizzt-clone. Ever. I've seen plenty of Drizzt-clones, but every single one of them dumped the "angst" factor. Many of them dumped it for "no personality whatsoever", but that's teenagers for you. Hell, I saw more angsty Tanis-clones (I may or may not have played one of these. I cannot confirm or deny!).
In the end it doesn't really matter what we think, but WotC aren't idiots. If they're making FR the default and putting Drow in the main book, hating on that really is peeing in the wind, because clearly WotC think that is what sells, and as they explained, the only reason that they didn't do this in 3E and 4E is because they were "afraid of the backlash". I think now they've realized the backlash will be largely limited to "Older Males On the Internet", and maybe it won't be so bad.
As for Orcus - he's the definition of niche - tons of villains are better-known and better-liked. That people on ENWorld might like him lots (thread suggests that they actually do not, actually!) rather proves my point - ENWorld is just one of several D&D communities, all with different likes and dislikes (I like ENWorld, but I can't pretend it's more representative than GiantItP or Dragonwhatsit or RPG.net or whatever).