Other common modes of transport that lack fixed schedule, route, or stops:
- biking
- micromobility (scooter-share, etc.)
- walking
- dial-a-ride transit options
But they have other cons as well. You need to have good bike lane infrastructure or to be confident taking the entire lane, whereas most everything is already created around the car or increasingly being created around the car (in the case of the developing world beginning its nascent highway networks). You have to have fair weather or be able to pack around gear like rainpants wherever you are going. You probably make use of the cargo capacity of your car once a week when you buy groceries and goods from stores that tend to size their products around that sort of interval of a trip. I ride my bike plenty but honestly when I go to the grocery store three blocks a way I am usually taking the car, because its easier when I realize oh crap I need milk, I need a gallon of vinegar, I need paper towels, I need toilet paper, I need olive oil, and that alone will overload the panniers and be nigh impossible to get on the bike, especially the paper products and their awkward bulk. I haven't used my panniers for groceries personally since I broke three eggs in a carton with them once. I either walk and grab a small handful of things or just take the car most times.