What evidence would falsify this idea that wealth alone gives you political power?

Agree with sibling that this is a straw man. The state exists to protect and serve the capitalist class, not particular capitalists. Actual state policy generally arises out of conflicts between factions within the capitalist class, striving either for direct benefit or for different guesses of what benefits the class as a whole. But the capitalists don't have to provide any benefit to the state to earn its protection, as in your model. It is literally what the state is for.

This straw man doesn't merit falsification. Nobody claims wealth alone gives political power. Wealth applies leverage to all endeavors, but political ends still require strategy and operationalization. It's just a lot easier with a couple trillion dollars, vs. a single individual vote once every couple of years.