Workers, especially drivers, have rights in the UK.

How else are you going to lower costs?

Yep, it does! However the net benefit to society at large - and being public transit, to the less privileged in particular - is still gigantic compared to any of the alternatives, and this is blatantly obvious if you've been in multiple countries/locations that use this system, as well as ones that don't use it. The job is generally still better than driving for e.g. Amazon, as well as honestly a whole load of 3D jobs[1] that we rather forget exist and people carry out every day, including in "wealthy" countries.

Perfect is the enemy of good. This is the #1 thing other progressives need to learn. Everything is a tradeoff.

[1] https://en.wikipedia.org/wiki/Dirty,_dangerous_and_demeaning