Why don't you see tents, graffiti, needles and human feces on the sidewalks and parks in Scottsdale, Arizona?

A few reasons. No overnight parking or camping, and they will roust you. That's pretty much everywhere in the metro area. Plus, the heat. Summer is quite literally lethal. We have homeless wandering around. I think the west coast is more attractive because the climate is much nicer, which is why (partly) that SD, LA, SF, Portland, and Seattle have more homeless. If they have a choice, they go there.

We did have a tent city ("The Zone") that the city ended up clearing out (near downtown Phoenix). We had a mixed government at the time (Rep legislature, Dem executive).

Scottsdale is like a huge HOA. The city has all kinds of rules about what you can and can't do, from house colors to commercial signage. And that's before the actual HOAs.