The best bet would be to use oil that is recommended by the car company.
anyways in my corolla 2008 model, toyota lahore put 20w50 in it themselves.
For new cars, obviously you are not going to put 20w 50 in it.
Regarding people in Saudi Arabia, they don't really care about their cars. They will run the car 10-15000 km on the same oil. Most of them do not even check the oil levels.
majority cars on the roads do not have proper tuning and are throwing raw petrol out of their exhausts, and one gets seriously ill on smelling them. This point is at extreme levels during Hajj. Because petrol is basically cheap over there people do not usually care about this point.