Delivering more, doing brain work more efficiently than all your coworkers are all easier if said person has a higher IQ leading to their successes in promotion, if they choose to not to place in much effort then that's another issue but the fact that a higher IQ person has the potential to utilise information more efficiently will eventually lead them to earning more money long term.
Yes, and higher IQ individuals do earn money in their lifetime, on average. The statistics show this. The gap in earnings from that increased productivity, however, will not be disproportionately higher than their job position and title would warrant. A higher IQ is like an XP boost, but it's not a cheat code.
If someone can utilise the market by convincing consumers to buy their goods/services and make a successful business model out of it then that's high IQ enough to me. Unless you've got examples to show otherwise? Don't care if they don't have a math PHD or aren't smart as the top 0.5% at a college campus, they are higher IQ than average. Of course many of the times people can get lucky, but most of the times you can't create a successful business out of mostly luck.
Keep in mind that the successful businesses that you see are an extreme minority. The overwhelming majority of businesses fail. Those failures are not necessarily indicative of poor business planning, management, acumen, or any other factor intrinsic to the business or business owner/operator.
I'm using the term "high IQ" to refer to individuals who score in the genius range or higher (130+), by official testing standards. You don't need this level of problem solving capability in order to build a successful business model. It's literally not rocket science.
The smarter you are, the more scenarios you're able to anticipate and analyze. This generally results in a higher risk aversion. This usually translates (in what you see in the workforce and in business) to the highly intelligent person often working for the lesser intelligent person who then assumes all of the risk (in the company, for example). Out in the ancient wilderness of our ancestral past, this would be when the smarter caveman lets the dumber one try out the new mushrooms and berries first to see its effects.
Bezos and Musk are above average in intelligence, have excellent business acumen, and their personalities invite plenty of financial risk-taking. Underneath them, however, are entire teams of brilliant scientists and engineers who are the brains of their boss' operations, innovation, and R&D efforts. Have you never asked yourself why those high IQ people working for these household names don't just splinter off and start their own mega corps? Well now you know why.