It's true: the old ones are very good, the recent additions to the Ender series for instance are terrible, they're an obvious cash in on his brand, I suspect he writes them quickly so he can make some quick cash (or to fill up his existing publishing contract.) and spends the rest of the time on stuff that doesn't suck so hard.
A review I read of his recent story collection said his recent stories didn't have to try so hard, he knew they'd get published and he was more or less keeping a hand in, his earlier work he's working hard and striving for quality, this applies in spades to the rest of his recent work and may well apply to any entity's (sometime) fall-off in effort or innovation after they've succeeded.
I agree that Card's writing is not what it used to be, but I don't think he's crassly cashing in on his past success. I think he has simply lost his touch (or at least, he no longer has the touch that appealed to us).
His early works were written when he was still relatively young and passionate and had years' worth of crazy ideas swirling around in his head. Fast forward 25 years, he's written all the good ideas he originally had, and he's now a middle-aged Mormon father and conservative political activist. If you read his books nowadays, you'll find they're pretty much what you'd expect from that description.
A review I read of his recent story collection said his recent stories didn't have to try so hard, he knew they'd get published and he was more or less keeping a hand in, his earlier work he's working hard and striving for quality, this applies in spades to the rest of his recent work and may well apply to any entity's (sometime) fall-off in effort or innovation after they've succeeded.