Then there's the fact that even the 18-20yo "Hippie Pilgrim" demo, which has held up pretty well for generations, is secretly stratified by the socioeconomic status of the parents. One's take on it depends on the specific cliques they're exposed to.
FWIW, the parent's comment matches my dad's sentiments about the city in the 60s/70s, but I wouldn't start a bar fight to defend his honor on this point. I would be genuinely curious to hear you elaborate on the changes. I live around the corner from the Upper Haight and it has always been one of my favorite parts of the city, but it has always had a lot of loafers doing nothing but drugs as long as I can remember.
Before the citywide affordability crisis, I think you were more likely to end up outdoors because you hit bottom than the other way around. The outdoor segment and the weed-dealing segment have always been more visible, though.