Yes, but this assumes a relatively sparse population so that there is more of a countryside outside the perimeter.

True, my 'frame of reference' is the description of the 15-minute plan in Oxford. Having visited Oxford, it seems that it would turn the city 'inside out' (as I described). In larger cities (like yours), it would simply 'create cell blocks'.

I still argue it will radically alter property values.

Katie Hopkins explains the 15-minute cities plan in Oxford: https://twitter.com/77eight8/status/1622361710379122691