Earlier quoted context omitted.
Was with you until that "twenty miles ... still wouldn't be possible." I ride my bike 20 miles to work frequently; its nowhere near as flat as Silicon Valley (Iowa is hilly). And the weather is often worse here. So maybe readjust 'not possible' up a notch or two?
Really, I meant say "no easy", in fact I did: When where one's work is twenty miles or more from one's living space, one just isn't going to easily bike to work. I slipped and said "not possible" later so jeesh, sorry. I meant "It's possible for it to be easy enough for the average person". I've commuted further distances myself but the average worker isn't going to do it. Sad but there you are.
As for the effort, the average person can do a whole lot more than they think. I ride with 20,000 Iowans in a weeklong 400+ mile ride every summer - aged 6 to 60 - 40 to 100 miles per day, pretty average people.
The only thing that makes the average person unable to do this is, they think they can't.