Interestingly, if you assume these are the only ways a startup can fail, and that for a typical startup creator (who is self-selected as smarter and more conscientious than average) each of these has an independent 90% chance of working out (what seemed to me like a reasonable estimate), then the overall chance of the startup succeeding is 0.9^21=0.11, remarkably close to the actual base rate. This particular model is unlikely to be accurate, but it is another way of illustrating your point.
Interestingly, if you assume these are the only ways a startup can fail, and that for a typical startup creator (who is self-selected as smarter and more conscientious than average) each of these has an independent 90% chance of working out (what seemed to me like a reasonable estimate), then the overall chance of the startup succeeding is 0.9^21=0.11, remarkably close to the actual base rate. This particular model is unlikely to be accurate, but it is another way of illustrating your point.