Like so many safety issues we will only really know the statistical answer looking back.
The move to twin engines was paralleled by increased reliability of engines and redundancy of systems and more obsessive maintenance processes and the flight crews desire to arrive safely too on failure of engine #1. The sum of those factors is still being calculated
The Customer is a realist: They like cheap flights and if the chances of making it to a safe landing are increasing vs last time they don't care much about the reliability of the most reliable parts . . most are more scared of a nut-case fellow passenger