If it's not a necessity, it's hard for people to maintain habits, particularly physical ones. The reality is many people are just not very disciplined if there's not an outside factor forcing them into it.

There are many comments here about missing their commutes as they could meditate/reflect on things, etc. One can quite easily do this with meditation or walking/running/biking for ~30 mins. However it takes discipline to carve out that 30 mins and leave it specifically for meditation or whatever.