Reacting mostly to the ending/conclusion here. I don't know about other founders, but for me, startups are basically the only vehicle for solving big problems that nobody else will/can solve. Often the reasons that (nearly) nobody else is trying to solve your exact problem are 1) it is risky/unlikely to monetize well, 2) it is hard, grueling, or boring work that may not even function right in the end, 3) might believ…
What you probably mean is that startups are good at innovating a potential solution to a big problem. But this is an entirely different thing than actually solving it at scale, and is the reason many startups end up getting bought or acquihired before they do anything of large importance.