I hear that often, 'ooh, I could have netted you much more'. Take it with a grain of salt.
Realtors have a professional duty to their clients, failure usually provides some recourse to the injured party. Builders and investors don't have any such structure in place.
I as a legal holder of property, have the right of use, and disposition of. Could it be that it was not the sale itself, but some boosting broker that created your grief.