I consider this a complete non-sequitur.
The idea that it is money that gets you elected has been proven wrong again and again.
What matters is Ground Game, community outreach, lots of spokespersons to flood the media channels. And a candidate that comes across as "authentic".
But is IS true that Democrats and Republicans see it as their primary job to collect donations.
With how the US functions for elections, there's also a tactical element involved. Media coverage requires money, as does outreach and spokespersons. But where that money is spent geographically also matters a lot. For example, while it's technically possible for California to flip to a Republican vote, it's so extraordinarily unlikely as to be implausible. Realistically, if CA flips... it means that R wins in an incontrovertible landslide. As a result of that dynamic, it's not really worth either candidate spending a whole lot of time, money, or effort trying to convince Californians of what they're already going to do.
There's a marketing concept that comes into play here, where potential customers are split into four cohorts: The Sure Thing, The Lost Cause, The Sleeping Dogs (more recently rebranded to Do Not Disturb), and The Persuadables. Sure Things are just that - they're the people who are going to buy your product (or vote for your candidate) pretty much no matter what. There's no need to spend money advertising to them, or at least not anything more than the basic level of acknowledgement and appreciation. The Lost Causes are the flip-side to that - they're never going to buy your product regardless of how much you spend trying to win them over.
Sleeping Dogs have always been the cohort I find most fascinating. These are the people that have a reasonably high likelihood of buying your product as long as you leave them alone. If you reach out to them, you end up either annoying them or your end up prompting them to shop and it increases the chance that they'll choose your competitor instead. This one is really interesting to me, because Gen-X is absolutely bursting with Sleeping Dogs - we just want to be left alone in relative peace with minimal disruption... and by and large Gen-X really dislikes advertising. And since the demographics of the largest voting block is shifting as Baby Boomers decline, the effect of this cohort is likely to make for very interesting times.
At the end of the day, marketers (and smart politicians) focus on Persuadables - those who are most likely to be influenced by advertising, narrative, etc. In terms of politics, that ends up being Independents, as well as moderate Republicans and moderate Democrats. It also means that most of the efforts should end up being in states that are purple, or are light blue or light red. In those states, Dems and Reps tend to have smaller margins between them, and usually you see a higher proportion of Independents. It's common to see situations where the electorate ends up being like 45% D, 43% R, and 12% I - and that Independent block is entirely capable of turning the vote.