It can be, but isn’t the most realistic starting point for someone out of shape to go from being overweight and driving already for 45 minutes (without traffic) to cycling 40-50 miles each way.. also people have kids to drop off/pick up, errands to run, etc. don’t think in the US its reasonable to say “the vast majority do”. Most American cities are not known for their bike friendliness..

Great that you can do this and it is a great thing to do, but saying that a vast majority has this option (at least in the US) and just choose not to is blatantly false. Distance is just one of the parameters, but so is the infrastructure, weather, being able to shower at work so you don't start a morning meeting all sweaty, time needed to get the kids ready for school, etc. etc. It just isn't viable for many people, even when at surface level it seems like it should be.