Not really. Acura sales have gone from 210K in 2005 to 136K in 2002, Infiniti from 138K to 80K. Over the same time period, MB went from from 244K to 325K. Lexus has consistently sold in the upper 200K/lower 300K.
Data is from goodcarbadcar.net, and they don’t have data prior to 2005.
Obviously, VW’s attempts to go upmarket have completely failed, and Mazda decided to abandon Amati entirely.
I guess Acura and Infiniti enough to con’t to justify their’ existence, but neither of them sell more cars in the US than, say, Buick (and I don’t think anyone would think of Buick as being a strong seller in the US). And I assume part of the reason Acura and Infiniti still exist in the US is b/c many of the cars were also sold in Japan (or, in the case of many Infinitis, were lightly modified versions of Nissans).