It is not sad, except maybe for those who do not keep their equipment long before selling it...and even then it is not sad, because no one is forcing them to sell so soon/often!

For everyone else, it is great! A 10D, 20D, or D70 for just a few hundred bucks is a good deal! On an absolute level, they are no less good than they were when they were brand new...and even on a relative level, compared to the models that have replaced them, they still aren't that bad.