People correctly blame the Character Builder for the death of third party stuff. Even if you produce quality 4E stuff, besides adventures, who's going to buy it? Those five guys on a mac who don't want to boot into Windows? That does not a market make.
The Builder makes it so easy to make a dude that any info not in the builder is useless.
What this tells us is that the only reason there was a third party market in the first place was because there was no builder for 3E. There was E-Tools, which I believe gave people cancer, but nothing like the Character Builder.
It should be no surprise to anyone that WotC can put out more stuff faster of higher quality than anyone else. The only reason people bought third party stuff in the first place was because there was no easy way to use all the WotC stuff.