I know what you mean, in principle. All the console makers will make various attempts to move outside whatever demographic they know they are currently good in - as a result you'll see games that probably would sell better on another platform for all three.
On the other hand, that doesn't negate that in many cases it is very likely that such titles would sell better on other platforms.
MS aren't backing Lips, etc. because they know those titles will sell like hotcakes on the 360, they're doing it for precisely the opposite reason. They know they are shooter/online centric with a certain demographic and are trying to extend. They're willing to take the lower sales, etc. in the process.
Same with titles on Wii or PS3.
As gamers we only want the games though, we're not (well, fanboys aside) worried about the console makers efforts - we just want access to the games. That's why non-Wii owners will grumble if they see a Wii exclusive title that suits (potentially) the HD consoles better - and vice versa as well I would imagine.
Try to be reasonable... its easier than you think...
