Surely anyone can do these activities in their leisure time. My point was that if someone's commute is spent largely doing things like reading or listening to podcasts, one would not share GP's inclination to spend part of one's prior commute time working, and have one's employer reap the benefits of that.
I have commuted on trains at various times and used my commute time in this way. Also, where I live in CA there are lots of people who bike to work (pre-COVID) and enjoy the forced exercise of their commute. Perhaps this is unique to warm-weather locations, where biking is easy for most of the year?