Why so few bike parkings but motor cycle parkings are ubiquitous ?

Not everyone rides a U-Bike. Why can't the city make it mandatory that every few hundered meters there are a few parkings, specially in the city center ? One way could be that larger companies and public offices such as banks, post offices to place some racks. To be consistent, city should definea consistent parking design and make then easily identifiable from a distance. One idea is like this: