I think few people truly believe money guarantees success and that's rarely claimed from my experience. There are plenty of other factors that need to be met to start a successful business, but if you have money, those other factors can be focused on more intensely and you'll be less hamstringed on factors like timing and time to market, innovation/added value, network effects/marketing, and so on.
You're working at a disadvantage in most other aspects needed for a successful business if you don't have a certain baseline of capital to work from. Often times more capital infusion beyond that baseline can help. There are certain problems addressed by startups that throwing money at no longer helps and you can reach diminishing returns. That's a nice problem to have.
To your point, money can buy you a Monte Carlo (or MCMC for 'better') approach to market exploration for your businesses products/services. You can try, fail, and adapt.
For many without piles of money, starting a business can afford only one failure (if they're that lucky) in their lifetime. No retries with refinements.
Since then, for about 5 years I did full time corporate work while they failed maybe two dozen businesses. The nice part is that out of those failures, two companies took roots and basically now they’re a lot wealthier than their parents and they long since paid of all the money they lost during those years.
While the rest of us need to get funding from experienced investors who vet our plan first. In a system where there are investors looking for people to invest in, this approach is bound to succeed more.