Your observation that 95% of the alternative schools are in urban communities is interesting. This likely sparks debate if minority students in urban environments are more likely to be placed in an an alternative school environment --- and if this helps or hinders their progress. A;long with the typical school to prison pipeline commentary.
The other question is if these alternative schools in urban areas are charter or private schools --- or are nearly all of them public.
I grew up in the suburbs but very close to large urban communities.
I can not remember any alternative schools in the suburbs nor in any nearby suburbs but I do remember alternative schools in the nearby big cities (e.g. Chicago). In addition, I do remember a problem-violent kid in my neighborhood...the parents pulled him out of school and homeschooled him plus they had private tutors/weekly sessions at a psychologist to help them...
They could easily afford it.
- The kid went on to get into Princeton.

Thus, maybe the suburbs are better (have reasons a school district may listen to) at fighting their school district about alternative school locations than those in urban communities.
wrbtrader