If I recall correctly, the whole point of the Windows NT family (which includes Windows 2000 and XP) was to ensure higher reliability by getting rid of the DOS legacy. In contrast, the purpose of a mainframe OS is to offer strict backward compatibilty for legacy applications, that is why "you will never see this on a mainframe OS".
Also, I believe that a lot of the problems with running SCI1 games nowadays have to do with the fact that Sierra did such a lousy coding job on that interpreter. Even "back in the day", getting some games (*cough* Quest for Glory 4 *cough*) to work properly (on the intended platform!) was an exercise in frustration.
Gentlemen, you can't fight in here! This is the war room!