>I've continuously encountered groups of 20-50 homeless people living in Boston, NYC, Miami, etc.
This just just not true.
About the only way to get 5+ homeless people in one spot in any of those cities is to do something that specifically encourages them to show up, like a church giving out free lunches on a Sunday.
I can't speak to Miami but I've commuted into (like train and walking, not just the highway) NYC and Boston, the latter more recently, and the most I've ever encountered with any regularity is groups of two (usually a pair of dudes who seem to look after each other's stuff). There are some panhandling points on the subways but any one point won't be occupied every day. The density of homeless is low enough that doesn't happen.
Your description of Germany fits with my observation of NYC, Boston, Newark, New Haven, Baltimore, basically the Boston-DC corridor.
A group of 5 homeless people in each of the cities i've lived there would have been a huge group.
I've continuously encountered groups of 20-50 homeless people living in Boston, NYC, Miami, etc.
That's an order of magnitude more than what I consider "normal".
The west coast is another order of magnitude higher, with groups of 100s of homeless people around seattle, san francisco, san diego, LA, etc.
But that not makes the situation in the east coast cities i've visited "good". I consider the situation in the east coast "horrible", and in the west coast "war-zone like", when compared with the cities where I've lived in europe (madrid, barcelona, milan, munich, stuttgart, etc.).