Where do you live though? In many parts of the country the weather is not conducive to biking regularly. If you visit colleges on the west coast you'll notice an infestation of bicycles but they have very nice weather year round so it's practical to rely on bikes to get around.
In cold places during winter, bike lanes double as extra room to pile snow. The trade-off is that in the spring the bike lanes are unusable until the city sweeps the streets because all sorts of debris accumulates in them. Tire-unfriendly stuff like glass and screws.
