An important part of the scarcity and invitation system is the way it creates artificial loyalty. Imagine the storm of complaint over the problems the 1 had if people could make casual purchases. Instead we have muted, almost apologistic, posts mostly out of sight on their forums.
Just like the 1p1 by the time anyone can just buy one the hardware and price will struggle to compete with year old flagships at year old flagship prices. The service will still be bad.