That’s not really true. The first fuel injection systems were mechanical. The first one of those used in a gasoline-powered 4-stroke car engine was in 1955. Bosch mechanical FI systems were common in higher-end European cars from then on. Digital electronic fuel injection controllers weren’t common until the 1980s, though there were some EFI systems controlled by what were essentially crude analog computers as far back as the late 1950s. I know that Volvo had such a system in the late 60s since I owned one. It was extremely reliable.