Yikes! I've never seen whitewater like you describe. I did have a rubber boat that we'd (as junior high kids) try and float our local creek after a rain. Life jackets were never a thought and the boat would fold as you describe if we didn't sit in it right. It usually got punctured along the way.
We have a 'white water' river or two here in Texas with the most used being the Guadalupe. I think it goes to class IV in some of the chutes and falls. Did it in a canoe a couple times and won a case of beer going over a falls and keeping the swamped boat upright, once. Kayaked part of it last year and got blown clear out of the boat going down a man made chute. All the true white water, sans a couple WW "park and play" parks, is a 4 hour drive for me, so we don't mess with it.
I mostly fish and paddle flat water. No gas, oil, registration, insurance, trailer, or licence fees. I can pile as many as 4 boats on top of the car. The only thing I miss is being able to blast across a lake to the hot fishing spots.
I've got a twin engine fast boat for that! <img src="/forums/images/graemlins/grin.gif" alt="" /> I do love the peace, quiet, grace, and portability of the kayaks/canoes though. The ability to 'stealth camp' out of one is amazing! Plus, if you use UL thinking when you pack, the water line doesn't change much compared to some of the other folks I've seen. Even though, you can bring just about anything you want!