I wouldn't mind having one, but I am single and retired,so don't have much use for one, my current bikes, fulfill any transport conumdrums.
Yes,the costs are in the building of them, they are very much a niche market, although used extensively in NL , the ordainary Omafiets tend to serve as general cargo/ transport over in NL, 'Long' bikes & cargo's for delivery & School runs.