I don’t know what world In which a courier earns more than a administrator in a company or even a middle level manager in an organization but it’s certainly not the world you and I presently live in.
Couriers may work for longer hours or all day delivering packages and may get bonuses depending on the number of successful deliveries made. The combination of wages, bonuses and tips earned wouldn’t sum up to half of what an administrator in an organization would make for working same hours.
Just about anyone who could drive okay could get a job as a courier but not everyone could successfully manage and run smaller units or the whole of an organization.
Any country will suit. I will try to compare. Administrator works 5 days a week, 9 to 17 and has a fixed salary. Courier can work 7 days a week from 9 to 21 plus he get tipped. In my company sys admin earns around 1900 EUR, while courier earns around 100 EUR per day minus taxes delivery app fee for same working hours. Lets say it would be 60 EUR netto. Add more 2 working days or hours and courier earns more. Anyway he wont be able to work in such tempo for months.