BD is already a success. Not from a monetary standpoint, but it is the next generation disc format.
Whether or not BD will be a monetary success for Sony clearly remains to be seen, but it is not foolish to guess that either (1) it won't be profitable for Sony in the end because it will not be fully adopted or (2) it will eventually be fully adopted and will be profitable for Sony.
A lot has to do with how prices of movies come down. And that's something Sony doesn't want to see because it wants to make more profit from BD than it does from DVD. The whole point of the BD format is to secure and increase Sony's movie-based royalties for the future and BD looks like it may not do that.
However, there is no reason to care because Sony will continue to support BD, profitable or not, until there is little demand left for the format. Unless you care about Sony personally, which would be foolish because they don't give a shit about you except for the money youc an give them, there's no reason to care if they make lots of money from BD or if they lose money from BD.