Don't long walks qualify as "real exercise"? The op's weight loss seems to indicate so. Even without the results, you can't discount the fact that they might get far more enjoyment out of long walks than being crammed in a smelly Gym each day. It's not always about being efficient with your time. Often the most enjoyable things in life are the least time efficient.
In my case, I'm not sure. I had a long history of being a member of gyms to where I did not go because I always found something better to do. In fact, in the past I even was paying for two gyms and I did not go to any of them. I suspect I'm not alone here, if all members of a gym decided to go, they would not fit in the gym. I always hear that the lion's share of revenue for a gym comes from people who never go.
I think that what worked for me (goal: increase activity) was to build the activity as a part of routine that was too inconvenient to skip, and then ending up liking that routine. I do not see anymore commuting as busy time, for me it is part of my free time, an activity that I do want to do. In other words, on weekends I now usually go hiking and I do not consider as busy time.
