There is nothing that says a company should only pay it's employees on terms it can only strictly control.
If you don't want to pay someone for 4 hours of commute per day, maybe dedicate some time to locating a closer place for them to live and paying for a move. Like you said: there are other ways to deal with it.
Indeed. This is basically the power imbalance in action - 'he who has the gold makes the rules'.
If employers should not pay for events out of their control then employees should not work if it exists out of their control (e.g. shift work).
In this case though the premise is wrong. Take a McDonalds restaurant in central London. Their workers have to commute. The store knows this. The workers don't choose it out of some sort of work life balance decision - it is impossible to rent downtown on minimum wage (as in, literally the rent is greater than 13K GBP a year).
If you don't want to pay someone for 4 hours of commute per day, maybe dedicate some time to locating a closer place for them to live and paying for a move. Like you said: there are other ways to deal with it.