Alas, pricès would have to greatly decrease; I have yet to find a recumbent bicycle that is less costly than all the four automobiles I have owned, even should their pricès be summed together. Though I must grant that all these were previöusly owned, a recumbent--or any quality bicycle--remains almost ruïnously expensive.
Now I bring into consideration this: The vast majority of velomobiles are recumbents; diamond-frame velomobiles are no mere exception, they are outright a rarity.
Futhermore, velomobiles with but two wheels are also rare; most have three wheels, a significant minority has four. Of all velocipedes that I have viewed, recumbent tricycles have the most dismaying pricès that ever I clapped eyes upon (I dare not imagine the cost of a recumbent quadricycle).
And yet that--even that--is not all.
The velomobile, by its very definition, has a weather shell.
And with that, "costly" becomes but a word.