This, rental car is a car driven roughly, in mud, in rocks, with rash driving, rarely serviced or poorly serviced, poorly driven, in potholes, or quick acceleration or quick braking can not be further than truth
How many times one rents a car for personal use v/s on official use or business use? Business use is way higher than personal use. Most of the people who rent it for business use, are reporting to their boss or some kind of supervisor; & if they thrash car, car company reports/charges damages, it will come back to the person who drove it. So, no, a majority of renters don't beat cars because they still will be on hook for damages.
How many regular rentals need premium? None. Only exotic rentals might. Most of the rentals are run of the mill Toyota,Hyundai, Mitsubishi, mid size or mid range; the cars which are most of the time good for everyone. None of them needs premium. Although, this fuel thing exists. When I used to rent, I used to buy the cheapest fuel at any cheapest station. Now in own car,I go by only Shell Regular.
Rental are new, & new cars are covered bumper to bumper for about 36000, transmission till 60,000.
Yes, rental gets different drivers, but so do to some degree of non rental (family, friends, not common but still not zero).
So, as stated above,a 36,000 miles in a rental is not much different than same in a non rental.
In my opinion; there is a similar set of drivers who dont care for their own car, & almost most of them will not care for rental or friendly loaned too. People race their own cars, people floor their own cars.
My personal experience; my used car came with all shop visit records; verifiable, from Ford's system. Yes, it had about 4000 miles more than projected 7 years 150,000 miles on projected line, but that gap is getting less everyday with my moderate use (1000miles a month).
Rentals are beaten is a personal opinion. Any car can come out beaten. People who beat cars don't care if they rent it or own it. But beating a rental car might bite back quickly instead of beating one's own car.