Your list excludes what is probably the most common reason to start a startup, which is that someone thinks they're more competent than the 90% who fail, so the

Your list excludes what is probably the most common reason to start a startup, which is that someone thinks they're more competent than the 90% who fail, so they have a good chance of succeeding and making themselves rich. There is uncertainty in business, but execution matters a lot. If you have good reason to think you can execute better than most, then a startup is probably the quickest route to financial independence.