Part of the reason for this is that parents are scared to death to let their children of bike riding age out of their sight for 5 seconds.
The internet has scared everyone into thinking there is a child molestor/abductor/killer behind every tree...thus, kids aren't allowed, like we were, to just take our bikes, go out, and be back by dinner.
Besides, any parent who would allow that is likely to be arrested for neglect (I kid, but only just a little bit...would not be surprised in some communities).
That and video games...