Why do you suppose that the theater gets more suspension of disbelief than the silver screen?
Went to watch the theatrical production of Disney’s Aladdin the other night and was struck by the minimalist (at least, relative to movie sets) approach to the stage design. They had some flats, a giant turntable, stairs, some carts, and a pile of costumes, leavened with smoke and lights and I suspect a relative of the common forklift.
A feature film with that level of detail would be ridiculous (amateurish?) and only watched for the heaps of cheese that it would produce or else really solid work on the filming end. But the 11,000-seat theater place was packed for the second week running.
Are our expectations of the stage that much lower? Do we not focus on production value as much as we think that we do?