I only really see/hear about the guides in the company my wife runs (so 10-16). They are going out for a ride along the tow path tonight, I've cried out because I'm fed up of fixing bikes that have been left in a shed for 8 months through the duration of a 2 hour 5mph trundle, specifically the one that punctures 10 minutes from the end and suddenly it's all against the clock and argh! (in my defence I did say if she had a maintenance night last week I'd do the ride this week, but it's not happened).
Anyway, they almost all have bikes, they just don't really seem to use them much. They are generally polite, if often disinterested (we recently did a 'life skills' night and I showed them how to check fluids in a car and change a wheel which some of them enjoyed) but then that's just children. They have always been in their own world, I know I was at a similar age and would have been similarly polite, but equally disinterested. Our 'kid' is 21 in a month and they did just the same.
They are definitely molly coddled more, a couple of decades ago my wife wouldn't have had any children unable to butter a slice of bread, but now has to teach them how to do it, and how to use a sharp knife to cut onions, etc. because some of them just don't get exposed to those skills anymore as 'the kitchen is dangerous'. Although I know when ours was growing up we had lots of 'how old should they be before...' type discussions largely generated by worrying about the general public perception etc. It was often obvious that they didn't come with a manual. We just let them go to my dads for a weekend and they were allowed to be free range there (helped by him living in a much easier place to be free range, walk out of our gates, you were on an NSL country lane and rat run, hardly pootle about on your bike/skateboard territory.) I know my growing up experience was of little use when it came to being a parent (but then both my parents worked until 10pm and I was basically feral from 11 to around 18).
They are doing stuff, it's mostly indoors, or supervised somewhere. It really doesn't surprise me that they aren't out in random places doing random stuff anymore (around here anyway) it's not the way things work anymore and that's probably a mistake and I agree, a general underlying fear (even for those who should know better) is probably a big cause, coupled with modern day technology.