This is not to do with safety or flying qualities but presentation!
More like car rental where you rent a car with a few thousand miles on the clock with modern GPS then rent a beat up, smelly car with stained seats torn upholstery etc!
Sadly aircraft hire is expensive and when you climb into the smelly aircraft with stained carpets torn upholstery, broken plastic mouldings and radios from 30 years ago it will not impress your passengers or your sense if value for money
Pace