Of course it would be completely different - even at that time if safety was the priority.
Space-frame allows to create much safer and overall better design than anything production based because the production base comes with a lot of compromises made for passenger space, price, production process, different safety modus operandi etc. Space-frame can be designed 100% for the purpose it serves, i.e. it takes no handicaps from serial production. And it can be also cheaper - for sure. The reason why the cars were expensive was not in using space-frame.