The average person commutes by car 10 hours per week. The average person doesn't live a bike commute from their job. What you are describing as extreme distance is extremely average.
Then there is places that get extremely cold or hot.
Places where biking is very unsafe.
The fact that most people are physically unable to bike 30 miles.
The lack of an extra 10 hours per week to commute without giving up sleeping or becoming unable to pick their kids up or be there after school.
Most people cant bike to work or replace their car with a bike.
The US census which gives times not distances . The average person only averages 8-10mph on their bike and most take a more indirect route so as to avoid highways when commuting by bike.
I misspoke insofar as the average citizen taking 10 hours total by car in fact its 5 which an average one way commute time of slightly under half an hour. I believe it would be reasonable to suppose that the average commute time would somewhat more than double to aprox 1 hour 1 way for an increase in time cost of 5 hours per week.
Given the average persons existing time commitment and fitness I don't think an extra 5 hours and 100 miles per week on the bike is altogether reasonable on its face.
If you take the intersection of those who are at least median closeness, sufficiently fit, and have the time to spare probably about 10% of the pop could commute that way. If we would like to achieve anything like that we probably need to make biking a bit friendlier than it presently is.
Then there is places that get extremely cold or hot.
Places where biking is very unsafe.
The fact that most people are physically unable to bike 30 miles.
The lack of an extra 10 hours per week to commute without giving up sleeping or becoming unable to pick their kids up or be there after school.
Most people cant bike to work or replace their car with a bike.