Going back many years when I first started in the industry you would find many drivers would do tour/private hire work in the summer (that's where the money was) and then do local service work in the winter.
Now in my opinion some of those that sit in the higher positions seem to easily forget what it was like as a driver, not forgetting the university trained manager whose never driven in service telling a 40 year veteran how the job should be done and you start on the slippery slope of low morale. Add in the poor shift patterns finish 00.30ish and back in for 9.30am and you'll see why some drivers are choosing a more attractive work/life balance.