I don't think we have any way of knowing this. At some point, digital distribution is more cost efficient, but as we know current collectors still like physical media. What is true, in the general, is that DVD sales continue to fall, down almost 10% again last year. Fewer and fewer portable devices have a disc drive. It seems that eventually the DVD will become a format that sees less titles being offered. The reality is, many of the titles on MOD would never have been offered for wide release. On the other hand, on-line retailers don't have shelf display issues like stores do, so as long as Amazon and other want to keep offering discs, they will. It's a complicated topic. If it were not for the age of the animation collector, and their stubbornness to adopt downloads, we likely would have seen a different service than MOD already. Personally, i'm surprised it's made it this far.
The reason I asked the question is because the post to which I responded sounded as if there had been some recent news of losses at WA ("what I fear most"). If his point is only hypothetical, then I am not worried at all about it.