I have seen NSXs in Acura commercials, but no, they weren't trying to sell the NSX in those CMs. It was like 2, 3 seconds of NSX, then to rest of the Acura brand lineups.
OK, forget the TV commercials I saw. When I said Acura was most "hyped", I'm talking about since the launch of the vehicle, even before people were on the internet. I doubt if Honda had anything to do with them, but the media created a huge hype for NSX, and for good reason. Since the debut in the late 80's to most of the 90's, it was very highly regarded sports car. There were plenty of free NSX advertising done by car magazines, and if Honda determined that they didn't need to spend their own money for an overkill on advertising, it makes perfect sense to me. The point of advertising is to get consumers/people to notice your product(s). It was already done, many times over.
On if Honda/Acura should have mass produced NSX, I'm no expert, but you're probably right. They could've sold them a lot cheaper, probably around $50,000(guesstimate) and even cheaper in '89 to early 90's(I think, NSX cost only about $60,000 at launch). And I think we all agree that NSX's achilles' heel, even more than the lack of horsepower was the super high price tag. And yes, I think you're 100% right when you say more people see NSX on the street, more it helps with selling rest of the Honda/Acura brand. One merit I do see on Honda's decision to be real an@l about the exclusivity(I hope that's a real word) of the NSX is that, it did establish Honda(or Acura in U.S.) as more premium automobile manufacturer. A (HUGE)jump they definitely needed from just a unique, commute car manufacturer.