There is. (both example pictures above have a commercial development less than 10 minutes walk away).
The problem is that there isn't enough commercial need for every single development to have it's own commercial block -- we already have a large overabundance of commercial space in the US as it is, adding even more of it inside each residential development doesn't magically spring forth a business to fill it.
(this is true even at city-level densities -- as lots of urban 5-over-1 developments are struggling to keep their ground-level commercial/retail units sustainably filled)
And since we do need more housing, pressure builds to just convert the commercial back into residential anyway...
There is. (both example pictures above have a commercial development less than 10 minutes walk away).
The problem is that there isn't enough commercial need for every single development to have it's own commercial block -- we already have a large overabundance of commercial space in the US as it is, adding even more of it inside each residential development doesn't magically spring forth a business to fill it.
(this is true even at city-level densities -- as lots of urban 5-over-1 developments are struggling to keep their ground-level commercial/retail units sustainably filled)
And since we do need more housing, pressure builds to just convert the commercial back into residential anyway...