Numbers are huge. Even tiny ratios mean something like 10-100 stars go supernova every single second somewhere in the universe.
Sounds a lot? Only about 1 star per galaxy goes supernova per century. A lot of galaxies.
Mindblowing.
This analysis really doesn't work. Star lifespan is inversely correlated to size. A star large enough to just barely go supernova is only going to live for ~100M years, and as they get bigger, the lifespans fall rapidly.
(Why? Because gravity is what provides the pressure for fusion to happen, and so more gravity means fusion happens faster. For large stars, the luminosity is something like the mass to the 3.5th power. Also, convection works less well for larger stars, so as stars grow bigger, ever smaller proportion of the star takes any part in the fusion reactions in the core.)