Private hire is technically not a taxi. They can't pick someone up at a rank or on the street.
Or Uber drivers in London
(In case you're not aware) It's the same thing. Uber operates in London as private hire operator, so their drivers are mini cab drivers. Same rules (now: basic English and rules test, yearly car inspections, MOT every 6 months, cars must have TFL badges, etc).
... who are obviously not taxi drivers, so ... your point?