Some billionaires (or their foundations) do fund certain areas of basic research.
Examples: Simons Foundation, Moore Foundation, Sloan Foundation, Keck Foundation, Schmidt Sciences, and several others.
But most of them are in biomedicine: Howard Hughes Medical Institute, Chan-Zuckerberg Initiative, Wellcome Trust, and many others.
However, this is all small compared with federal funding: around 25% of academic funding is from philanthropy, and over 50% from federal grants. This proportion is much lower in STEM than in biomedicine, and much lower in less prestigious universities.
So historical evidence that fundamental research can be helped, but not entirely funded, by philanthropic billionaires.
Yann LeCun argues that billionaire philanthropy supports areas of basic research…
Brief
Yann LeCun argues that billionaire philanthropy supports areas of basic research (e.g., Simons, Moore, Sloan, Keck, Schmidt Sciences) but is dwarfed by federal funding — about 25% of academic funding comes from philanthropy versus over 50% from federal grants. He emphasizes most philanthropic dollars go to biomedicine (HHMI, CZI, Wellcome) and that philanthropy’s share is smaller in STEM and at less prestigious institutions, so philanthropy can help but not fully fund fundamental research.