I think the sort answer is that sales weren't sufficient, despite the relatively wide retail coverage. No doubt in professional and academic circles, the iPad proved irresistable. Recall that enTourage never issued a press release indicating rave reviews by classes of students at any institution, even though they did launch at least a couple of pilot projects.

enTourage had strong marketing, I think, with presence at trade shows, etc., but the wider public simply "didn't get it". As wrong as the professional reviews were, it seems they did accurately portray the average Joe's perception.

Of course, we'll never know for sure.