Well the other side of the equation is what the new distributors (Netflix, Amazon, etc.) are willing to pay to stream a given property. If a property keeps jumping from service to service and in and out of availability I would guess it has more to do with a mismatch between the perceived value of the property and what the streaming services are willing to pay for it.

Artificial scarcity is a thing I can't argue with you there, Disney has been doing it for years with drip-style "anniversary" releases of their properties on media. I would fully expect them to do the same with their streaming content.