Nothing to do with being responsible for lives etc.. etc.. so are Bus drivers and they don't get that level of pay. High pay is a result of a militant union and a career that is a semi-closed shop. They don't allow direct applicants - if it was open to more competition you'd find capable people willing to do that role for a substantial pay cut.
Yes, chance of a bus crash is immensely higher than chance of a train crash. Knowing routes, seriously, it's on tracks, there are red lights and should be an indication at every change of speed and gradient. Ultra concentration, the thing stops and starts constantly. You have turn around and breaks.
Having to deal with the public and getting scorn from them, seriously, in 15 years using the tube constantly I never once saw anyone scream at a driver, it happens to workers on a platform, people in ticket offices but both still extremely rare, but people bother to walk to the front of a train to scream at someone, literally never.
As you say, the job is paid way more than other similar roles because of unions and importance of the job so when they strike unfairly the other side gives in pretty quickly.
Bus drivers should absolutely be paid more than train drivers. The risk to themselves(every single passenger walking right past and dealing directly with them) is far greater, the number of attacks and incidents like spitting and attempts to steal money are far far higher and the risk of an accident on the roads is far far greater.
