Classical, with its small core of devoted listeners, is pretty much the opposite of the music industry today. They want to hook people with a three minute single and turn that into a $13 CD buy. There is no way that they can do that with classical. First, the listeners are far too sophisticated, and, second, the CDs are often more expensive. There are not that many people who can drop $50 on a Parsifal or $25 on a Mahler disc set when the mood strikes them.
Sony is exploiting their back catalog to their advantage. DG, with the Classics series, is doing a good job. However, the Decca classics series seems geared to popular recordings. The only Decca Classics disk that genuinely surprised me was the '57 Walkure act 3 with Solti. I warrant that was designed to cash in on Flagstad.
Mahler is in a bad way in this setup, as he is a composer for those who have progressed well beyond Beethoven, Mozart, and the occasional opera aria. Mahler recording vary so widely and Mahlerites are so picky that it leaves the back catalog goons in the lurch. Gramophone's recommendation does not translate, despite DG's recent series, into sales. As I look at the situation, I think a private selection label, with special order runs of select albums is the way to go. I think that has been discussed here before. The packaging wouldn't be very fancy, but having a CD of the master tapes of a great recording has its advantages.