Money, on its own, carries no persuasion whatsoever — unless you're bribing people to vote for someone (which is illegal[1]). In reality, money buys you a platform to sell your ideas, some people like those ideas, and THAT'S what results in votes.
If you don't believe me, I'll start with anecdotes, and then close with data.
Hillary Clinton outspent Donald Trump by 2x in the 2016 election, and still lost. In fact, she had far more corporate backing than Donald Trump, and still lost.
In the 2020 Democratic Primaries, Michael Bloomberg spent $1 billion (!!) on his campaign, and won just 9.4% of the popular vote (1.38% of pledged delegates).
Tom Steyer (a no-name billionaire), spent $343 million on his election, and won a humiliating 0.38% of the popular vote (0% of pledged delegates). Interestingly, you would think he would have at least 1/3 of Bloomberg's vote, which suggests that the vast majority of the variance in Bloomberg's vote share can be attributed to his existing name recognition as a famous businessman/politician. No amount of money was enough to make their core message resonate with ordinary voters.
Bernie Sanders spent $195 million on his election, having spent less than Bloomberg + Steyer and while having handily beaten both. Joe Biden spent $105 million on his campaign, less than Bernie, and still beat him by 3 million votes.
Elizabeth Warren spent $121.31 million on her campaign, and also handily beat Bloomberg + Steyer while having spent far less than them, while losing to Biden while having spent more than him.
Those are just the anecdotes (of which there are many more).
Decades of research[2] suggest that money probably isn’t the deciding factor in who wins a general election, and especially not for incumbents. Most of the research in the last century found[3] that spending didn’t affect wins for incumbents and that the impact for challengers was unclear[4]. Even the studies[5] that showed spending having the biggest effect, like one that found a more than 6 percent increase in vote share for incumbents, didn’t demonstrate that money actually causes wins. In fact, those gains from spending likely translate to less of an advantage today, in a time period where voters are more stridently partisan. There are probably fewer and fewer people who are going to change their vote because they liked your ad.
Yes, money helps you broadcast your message. If your message resonates, you can even win elections (what a concept). But money alone isn't persuasive.
[1] https://www.law.cornell.edu/uscode/text/18/597
[2] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2605401
[3] https://journals.sagepub.com/doi/10.1177/0002764203260415
[4] https://www.jstor.org/stable/2138764?seq=1#metadata_info_tab...
[5] http://www.sas.rochester.edu/psc/clarke/214/Gerber98.pdf