You are not running the same numbers I am. If there are 1000 houses I'm claiming there should be about 100 retail shops. That people only get a haircut every few months is why those can't spread out.

You can run the numbers relatively exactly. 35% of income is spend on housing, which "disappears" (we can assume this will support some banks and realtors or whatnot), some is spent on this and that, and the remaining spent on "household, groceries, entertainment, etc" would be what can support retail shops. Then you just need to know how much it costs to run a shop, and you know how many houses you need to support it.

That sounds plausible. If you're talking about total shop count of any kind, then as a conversion factor between my numbers and yours we're saying there are 20-100 types of shops people visit with any regularity in a year. That sounds about right.