Hah! It's actually my 23rd birthday today. I've talked to a quite a few people about this and most seem to think we've been going downhill since at least the early 1990's. Some would point back as far as the 60's.
I picked 1999 since I don't think I've ever talked to someone who chose a later date than that.
Of course, people from 2nd world and 3rd world countries likely have different views.
Downhill in what sense? Downhill implies there’s some goal or ideal to strive for, but what exactly is that? Do you believe that this downhill is irreversible, or just another bump?
Lots of people take negative views on today, but it’s hard to reason about until you can nail down exactly what “good” is and why.
That question (i.e. exactly what ought we value) isn't difficult to answer. It is impossible to answer. So I don't let it get in my way.
I disagree with your second paragraph. Each person has some idea of what he values, and some idea of whether things have improved with respect to those values, a comprehensive survey of people on this matter would be somewhat accurate IMO.
I think it's you that are showing your age :)
Presumably you were 10 in 1999.... and it's all downhill from there.