Until now I had 6 bikes in my life, and over 20 years riding them. I have enough experience to know differences of different types of bikes. I also know how comfortable it was/is to ride them for hours.
Little scooters, like shown in the beginning of this thread, are not comfortable. That is no big deal when one uses them for trips around the corner, but it becomes pretty obvious on longer trips.
Sure, it's possible to take them on longer trips. It's also possible to walk or take public busses. But is that fun? If anybody likes to do longer trips, and can afford a more comfortable bike, why wouldn't you use a more comfortable bike?