what has been disproved was Darwin's intransigence regarding the existence of other mechanisms beyond natural selection that would be at play in the development / evolution of life
Please could you explain what new mechanism has been discovered that does not depend on natural selection?
Also where are you getting this notion from about Darwin's alleged "intransigence"?
That explanation is simplistic and very incomplete
Perhaps it is your personal grasp of Darwin's theory that is simplistic and very incomplete.
Whether changes in a phenotype are very, very slow and gradual or just slow and gradual it is still natural selection.