I don't see how New York Undercover's success 'scuppers' the race argument regarding the possible failure of Undercovers.
I forgot the term, but it has been standard practice for upstart networks to build a core audience among blacks primarily only to get their legs and then they move on the white viewers that they really covet. Check the programming history of FOX, UPN, and WB, and you will see that their initial content was far more diverse in terms of shows starring blacks than it is today.
And to be honest, NYU's success was relatively minor compared to other Dick Wolf cop shows (L & O anyone?). Don't get me wrong, it survived while some of its white-led contemporaries faded, and I don't want to knock its achievement. The show did a good job of cultivating its audience (which I would argue was primarily or heavily black), having a lot of musical guest stars, good production values, etc. As was mentioned before, NYU also benefited from being on a network that was trying to establish itself by first building an audience and was willing to give the show a chance. But how does one show (at least a decade old) that is barely remembered today affect the possible fact that Undercovers hasn't sparked much interest in white viewers? (And to be fair, any viewers. Because I don't know the numbers.)
There have been several attempts at action type shows in the US, with black leads or co-stars, by my recollection, with New York Undercover and The Unit, being the best ones, in terms of relatively long-term success (lasted over a season). Blade the Series, A Man Called Hawk, Fortune Dane, T & T died quick deaths. I would argue that the Unit, while having a black lead, also had an ensemble cast filled with whites so it wasn't necessarily a 'minority' show in the sense that most of the main characters were non-white. On the Unit, the majority of characters were white.
That's going back about 30 years now and most we've only had about seven shows with blacks as leads or co-leads. Compare that to the tons of white-led shows that come out during that time period and how can they be on the same plane? If a show with a black lead fails it takes Hollywood years to try the concept again, whereas with white lead shows, their race doesn't play a factor in suits hangwringing about whether they should try it again. They just do it and continue to do it and some fail, some succeed. I think if there were more shows with black leads it wouldn't be such an issue and there wouldn't be as much importance put on whether the one show of the moment succeeds or fails, or what its performance says about race relations or doesn't. But since Hollywood in a lot of ways reflects the twisted landscape of race relations in our country, it helps create these situations that make a show like Undercovers stand out more than it probably should.
I believe that if Undercovers doesn't generate heat race might factor into why people don't watch it. Some whites might not find the Blooms interesting or feel they can relate to them due to the color of their skin. Though I'm not willing to say that race will be the only factor if the show doesn't do well. It's tough for any new show to get off the ground and the demands on network TV to produce a hit, and especially the struggling NBC, to get back on track, have got to weigh very heavy on producing instant hits. There isn't any more time to let shows grow an audience. Though I think because NBC is struggling that they decided to take a chance on Undercovers with two black leads. If they were riding high, like ABC or CBS, you wouldn't have seen Undercovers on their schedule. JJ Abrams involvement doubtlessly helped the project get off the ground too, and I give him kudos for it.
I think a better indicator of how much race might play a role in whether the show succeeds or not is to put it on USA beside Covert Affairs and see how well it does. I mean, CA is a pretty frothy show just like Undercovers has turned out to be. Plus, on USA, you don't need to be a ratings giant to be considered a success.