I still try to from time to time.
It's not easy when you stop, and yeah there's definite risk of injury.
I was never big on slides or grinds, but I did like clearing stairs and gaps.
I couldn't imagine ollie'ing a 6 set now, but I do TRY to clear some minor gaps still.
I def try not to get hurt, but I like the exercise you get from skating. I think it's a unique way to work the back muscles.
Speaking of which,
My cousin a few years back (3 kids, and he's a pastor of a large church) was on vacation in Deep-Creek Lake, and for some reason ended up back on a skateboard. He broke his Pelvis.
He was probably about 40 at the time.