All the above:
- Place to securely lock a bike. The burden is on the employer for this and most dont want to spend money on this.
- Showers and places to change, locker room to store nice work clothes, same reason as above
- Takes time. You dont get as much sleep unless you are able to get to bed earlier, plus you get home later, can be problematic if you have kids, etc....
- Sometimes crappy cycling infrastructure. NYC is very proactive and has been, at improving this as they recognize the need to get people out of cars. It'll be curious if the new congestion pricing plan will send more folks to bikes