Whopity
All you say is true but it fails to adress the fact that most PPL holders don't have the depth of flying experience to take on the IR with so few hours.
I am sure that there are the occasional very bright students who could do it but I have only seen a few in twenty years of instructing. Much better these people build some experience with long flights over unfamiliar routes and then take on the IR when they have a little more time under their belts.