I saw that comment but can't say I buy that European roads are substantially interfering with TT training. Instead it's that pure power can shine through in a TT despite a lack of technical skills. However, more and more young Americans seem to come up through MTB ranks, which should help with the overall skill level.Bolder (above) suggests that perhaps long, straight roads in most of the US are conducive to TT training, compared to Europe's hilly, narrow, curvy roads.
What you need for TT training is low car traffic, not straight wide roads. It's difficult to find empty roads in the larger American urban zones due to the amount of sprawl; my (more limited) experience in Europe makes me believe that most cities are dense but surrounded by hinterland that is suitable for heads-down TT work. Of course these days you also have the option of Zwift, but a lot of people are probably turned off by the boredom of that.