https://news.gallup.com/poll/4708/healthcare-system.aspx
This isn't about who wins campaigns -- this is about who influences the issues they campaign on. Since the Citizens United decision politicians have had to switch to the Super PAC model to be competitive, which gives drastically more power to dark money donors. And unsurprisingly, as cited in that study, the influence of average citizens on politics has been completely surpassed by businesses and economic elites:
https://www.cambridge.org/core/journals/perspectives-on-poli...
Doesn't matter anyway because the poll doesn't mean shit. Most people are idiots and will answer the poll completely differently if you actually give them a realistic question like "would you accept a major tax increase to get universal healthcare?"
https://www.cambridge.org/core/journals/perspectives-on-poli...
Multivariate analysis indicates that economic elites and organized groups representing business interests have substantial independent impacts on U.S. government policy, while average citizens and mass-based interest groups have little or no independent influence.
Regarding the last national election:
https://www.brennancenter.org/our-work/research-reports/fift...
The Court’s decision and others that followed shaped the 2024 election to a greater degree than any that came before it. Most notably, Donald Trump substantially trailed Kamala Harris in traditional campaign donations, which are subject to legal limits and must be disclosed. Yet he was able to compensate for this disadvantage by outsourcing much of his campaign to super PACs and other outside groups funded by a handful of wealthy donors. While such groups had spent hundreds of millions of dollars on ads in previous cycles, this was the first time they successfully took on many of the other core functions of a general election presidential campaign, such as door-to-door canvassing and get-out-the-vote efforts. Their activities unquestionably would have been illegal before Citizens United.