The problem is that binary XML, while suitable for many situations, takes away one of the supreme advantages of Web services coding and text-based XML, which is the fact that it is human readable.
It's also highly probable that Moore's Law will kick in here as well, and new hardware will handily keep up or surpass the requirements of handling more bloated XML traffic. The catch is, of course, that more investments will have to be made in updated network gear and platforms. But, we've all been down this road many times before. After all, we even now have computers that can run Windows XP, don't we?