You do make a very good point. I was about to pay $190 for the MP shoes and then pay another $200-$300 to have them converted.
And that is also my point with regards to the PKE meter comparison.
(I am assuming you know about the PKE meter prop from Ghostbusters ? It was very hard to make and required alot of individual parts, semi-obsolete shoe-shining machines to cast the shell or use an original, electronics etc, etc. Complex and expensive. Then Mattel made a very acceptable replica for $75)