That we have 3D standards. Too many standards so when you look at PC Gaming some displays won't play along with the owner's PC.
Is it time for systems to become unitized? That is, is it time to disallow the current pick up some dozen things and hope it all works?
Samsungs SA950 27" 3D monitor cannot play over 90% of 3D content available.
Games make up almost all 3D content available.