For most people, the point is having a chance at being wealthy. Most founders believe they have a 90-100% chance of success, even though it's more like 0.01%.
Some others may start companies in order to get out of a painful career track or because they want to understand the process or some other ancillary reason, and they'll get more value out of the process than others would
More specifically the question is "what were the specific, direct causes of failure?"
"My car broke down" vs. "the alternator went out so my battery died and my car wouldn't start".
Years ago, there was a survey for founders called Startup Genome that asked about what went wrong.
It found that most companies failed because they had the wrong team or because they scaled prematurely (e.g. hiring full-time people to do part-time work).
My anecdata tells me most people never even get that far because they underestimate the cost of customer acquisition, and they can't survive the time it takes to get someone to write a check.