Not really.. HD 3870 wasn't that much behind an 8800GT, it was a good bit cheaper and slightly slower, until nVidia slashed prices a lot...
But starting with 3 series, AMD didn't try to make the best card out, they started putting out cards that are great in-terms of bang for the buck, high performance but low price... and so far thanks to just that strategy; they've been getting 95% of the forum's recommendations in the Hardware Section..
nVidia just did that with one card ^^ the 8800Gt..