"An individual with a 60 minute commute has to earn 40 per cent more money to be equally satisfied with life as an individual who can walk to the office"

This mixing of units is enough to call the whole paper into question. 60 minutes - by what mode. There is no reason you can't walk 60 minutes to work even though I don't know of anybody who does.

I have walked to work before, it took me about 40 minutes. I have also drove the same distance, takes about 12. I can take the bus which takes about 30 minutes (including 10 minutes walking to/from the stop). A helicopter could probably do it in 5. You can imagine other ways I could get to work with different travel times (practical is not a requirement).