Earlier quoted context omitted.
Empirically, once a campaign has enough money to get their message to the voters, additional money does very little to affect the result. So this probably doesn't have much impact at all.
Wouldn't the extra money allow their message to get better "saturation"? If they can get their message out and cover more ground, be repeated more often, etc. Doesn't that give them an advantage?
I haven't looked at the research myself, but among Economists this is an established fact.
To me, this is good news. The cynical view that anyone can buy an election by outspending their opponent is depressing, and I'm glad it isn't true.
BTW, it is true that the candidate who spends more usually wins. But that mostly just reflects that they're the most most popular candidate, so they get the most donations.