I think we have a disagreement in terms beyond "density". I'm talking about bicycle as transportation, and I believe you may be talking about bicycle as recreation.

To clarify, transportation is a means to get you to a destination. I don't know where you live, but I haven't lived in or ever even seen a suburb that provides all the destinations that a child (assuming they're old enough to ride a bike alone) would want to bike to.

Friends live in different neighborhoods. The mall certainly wasn't in my neighborhood. The video store, my church, the woods, the local pool, the public library, all required crossing streets which have become busier and busier.