Many of these communities are spread out. People don't live in apartments or condominums clustered close to transit stops. Instead they live in houses a long way from bus or train lines. A lot of people like to live this way. But it makes it hard to design transit systems for them.
Public transit works best when the community is designed around it.
This doesn't mean everyone has to be jammed together in dirty, crowded buildings. The train station is the diagonal line in the middle of the picture. A lot of communities also make it much easier to walk or ride bicycles. They can put the bikes back into another rack after they ride where they want to go. There are many different kinds of public transit.