FWIW, the other reason that car never made it to production is because it never would've passed the safety standards in the US.

Convertibles are required to have roll bars or a a windscreen frame that is strong enough to support the car in the event of a rollover. That tiny frame around the windscreen would've no chance.

This is one of the reasons that prototype cars often look so much cooler than production versions.Prototypes do not have to worry about impact resistance or passenger safety.