Oldest fella I met who I knew was an H addict was roughly in his 60s, homeless, lost both his legs because of it, as far as I'm aware he's still at the point where he'll do literally anything to shoot up. Feel sorry for the guy, he's not a bad person, just must've had a pretty tough life, and he probably didn't have harm reduction information when he needed it. Being on the streets obviously isn't helping him either. People are scared of him though, people generally are scared of homeless addicts of any age round where I live, unfortunately some of them are petty thieves, or are dishonest, so people usually ignore them all :/ (that's not to say that I do - I empathise, even with the dishonest ones, or the thieves, so I do what I can by going and getting them an OJ or a sandwich or something. I can't bear to walk past people without doing something for them)
I think with homeless addicts, it's gonna be either unsanitary shooting conditions, starvation, OD or even just the cold weather that gets them. Which is I guess why you wouldn't see many older addicts on the streets. Most of them here are 20-40. It's a really sorry situation, they're not even treated like human beings by most of the general public. The only help they get is from the hostels (which are too expensive for most to stay in anyway, it's often cheaper to just buy smack) or from the seriously under-strain drug services. Even then, those services can only do so much, because they're not government funded.. Like pill_billy says, it's easier to just leave people for dead than to fucking help them. Don't make addiction a healthcare issue, and you don't have to deal with what really should be dealt with by health professionals rather than fucking law enforcement. Sorry, I've gone kinda off topic, it's just something that really bothers and upsets me.
Oxy seems to either be the DOC of the young (I for one enjoy it a lot), or something that elderly folks get prescribed and become unknowingly dependent on. It's worrying, the trend for young people to start using it, because it is so good, and the jump from oxy to H really isn't all that far. Plus, it's a shitload cheaper. Even if people don't end up on H, there's a lot less stigma attached to prescription pain pills, so they're just more socially acceptable for people to be addicted to. Again, sorry, I've gone off topic.