From my knowledge of the horrors of printing and being the 'printer guy' for a Drafting department where we dealt with all kinds of interesting printers...

The scenario I'm theorizing, is that there's probably at least one major vendor who's drivers are dependent on this behavior, and Microsoft is trying to avoid the flack that could result from an update 'breaking usability'. Working around that behavior could be complicated. I feel like if this is the case, I know the vendor.