I think Apple uses 'security reasons' as a cover to advance their monopolistic business models, in a way to keep their platforms locked down, and a way to extract a minimum 30% transaction osst and yearly fee for access to their walled gardens.
Apple are far from a monopoly, they don't even have a majority of the phone market, their PC share is still in single digits.
A monopoly (from Greek μόνος mónos ["alone" or "single"] and πωλεῖν pōleîn ["to sell"]) exists when a specific person or enterprise is the only supplier of a particular commodity.