5) The lack of FTOs willing to handle private pilots (non ATP)
6) The huge lack of FTOs willing to handle pilots with their own plane
The above two factors inflate the IR process with a big disruption to one's life and extra costs and hassle (hotels, travelling, etc).
Whereas in the USA you can do the IR in the same school where you did your PPL.
I could also add the FTO moneymaking scam called the "170A flight test" but that may go away...