Employers pay low rates because the supermarkets are constantly putting pressure on all its suppliers to cut costs to keep food cheap,cheap, cheap. and those rates then roll across the whole transport industry. The rates Hermes pays its delivery staff are abysmally low and they ahve to use their own cars.
While there are enough people to take these jobs in order to have employment, they were stuck, but now there is a shortage, the boot is on the other foot, supermarkets caught between higher wage rates or no deliveries are paying up and I think the time is right for a charter of decent conditions for drivers, including not just working hours, but days at home, they should only work five days a week, the rest days should be at home, but if this is not possible they should get home leave in lieu when they get back.
The government response to the shortage was to increase permitted driving hours, but what else would you expect?