Part of the problem with biking culture in the US it is an evolution of racing/track/BMX bikes. These are designed for weight reduction and aerodynamics rather than comfort. Exposed chains are almost universal, necessitating having your leg cuff rolled up or rubber banded, if you try to wear normal clothes.
Meanwhile in places like The Netherlands and Denmark, bikes are built to be practical for normal people in normal clothes to ride in a comfortable position. Step-through bikes are the norm and are not considered "women's" bikes.
The first image on this page is a Dutch-style bike. The lower pics are the closest thing America has to offer. http://clevercycles.com/blog/2007/06/26/dutchness/
Notice on the Dutch bike:
1) UPRIGHT POSTURE -- for comfort rather than aerodynamics
2) FULL CHAIN CASE -- So you can wear *regular clothes* without getting grease all over them or having them get caught in the gears.
3) COAT GUARD OVER REAR WHEEL -- If you wear loose, long clothes like coats, jackets, or skirts (or a tux), it will not get caught in the rear spokes.
4) LARGE FENDERS -- Also to keep your clothes clean if the ground is wet or dirty!
These things add weight to the bike or add wind resistance. Sports bikes in the US shun all these things. Unfortunately, sports bike design has affected even "city" bikes in the US, which means that people barely remember what a full chain case or coat guard are anymore.
In the Netherlands, people go out clubbing on their bikes wearing their sexy outfits. Members of parliament bike to work wearing their suit and tie.
If we want people to switch to bikes in the US, we need features like these so people don't have the inconvenience of having to change clothes or roll up their pant leg (and still risk grease or nicks on their calves). These are all obvious solutions that are just not as obvious to American bicyclists because they never see them now.