Fisher’s failure and the dramatic end of neo-Darwinism

Dr Rob discusses a fundamental aspect of neo-Darwinism (Fisher's Theorem of Natural Selection) and how it fails mathematically. First postulated in 1930, Fisher's idea was promoted as something as firm and settled as the 2nd Law. Problem is, he made several incorrect assumptions that invalidate the whole thing. When you add realistic mutations to the scenario (e.g., Basener and Sanford's 'Fisher's Theorem of Natural Selection with Mutations'), you see that the net trajectory of evolution is downward. Why did it take 90 years to figure this out?

Links:

Basener and Sanford 2017 The fundamental theorem of natural selection with mutations
Basener et al. 2021 Dynamical Systems and Fitness Maximization in Evolutionary Biology
Keightley and Lynch 2003 Toward a realistic model of mutations affecting fitness
Price 1972 Fisher's 'fundamental theorem' made clear
Fisher 1930 The Genetical Theory of Natural Selection (Wikipedia page)
Carter 2020 A successful decade for Mendel's Accountant