I think you bring up an important point: there is a class of homebuyer who is both wealthy (or at least high-income) and a control freak. McMansion (or more specifically McMansion builders) target this demographic with empty shells, then let the homebuyer customize to their heart's content (even if said customization is stupid).

For some, it appears that the control is an important purchase consideration. The bank is the only one taking the risk.