Good point, I forgot Rice was quite a bit older.
Indeed.
His last season with the Ravens, he only had 600 or so yards after busting 1000 every previous year. The Ravens were already considering moving on from him. He'd lost more than just a step or two.
To further belabor the point, look at Michael Vick. Dude did hard time for animal abuse and had no problem getting on a roster when he got out because teams still felt he could offer something.
A certain ex-49er QB who won't be named is regularly pointed out to be not on a team because of his, here unspecified, odd pregame behavior. However, I'd wager if that guy was actually an elite top ten QB, he'd be playing right now regardless of his issue.