They have to play by the same rules as us. Having more Bitcoin does not give anyone control over the network.
If they dump their coins, cheaper sats for everyone else.
If they hold their coins, all other sats become more scarce and valuable.
Discussion
Whoever has the most fiat can acquire the most #Bitcoin plain and simple. And that is based on the flawed method of buying it with fiat as the only way to acquire it. #BTC has nothing to do with fiat.
Someone can build/provide a good or service in exchange for Bitcoin. Fiat is not the only way to acquire it. I agree with what you say though, Bitcoin has nothing to do with fiat.
Yes at the current stage, those with the most fiat can buy the most Bitcoin outright. When big fiat money gets into the space, (MicroStrategy, BlackRock, etc) Bitcoin price will rise against fiat. This is obviously good for those who front-run these people.
Those who did not front-run them will still have all the benefits that Bitcoin brings. Immutable property rights that nobody can take from them. The ability to store their energy in a form which will not devalue over time.
Those with more will have more purchasing power, but they won't be able to create more out of thin air. They can either spend it on goods and services, thus moving it to others who create value. Or they can hold it and help everyone else on the network by proxy.