I think the reason for this increasing complexity comes from efforts to be satisfy every single use case. When everybody starts pitching in in the creation of t

I think the reason for this increasing complexity comes from efforts to be satisfy every single use case. When everybody starts pitching in in the creation of the standards with their weird corporate use cases and actual specification writers try to satisfy each and every one of them. There is no reason schema specification has to be very complex. Instead, it can be made open for extension but be very concise and with clear boundaries itself.