It's easy to define 'cheap': relative to the wages market, market prices for driving are relatively low compared to other jobs. 'Underpaid' is a value judgment

It's easy to define 'cheap': relative to the wages market, market prices for driving are relatively low compared to other jobs. 'Underpaid' is a value judgment, you claim that prevailing market wages are unfair so presumably you have a better model to determine and protect higher wages.