Your summary is much more emphatic (“people”; “substantially easier”) than any of the research I’ve seen.
As for color schemes: any scheme which makes a website unreadable by the color blind will make it mostly unreadable by everyone else, too: human vision distinguishes shapes and details mainly via lightness contrast.
As for color schemes: any scheme which makes a website unreadable by the color blind will make it mostly unreadable by everyone else, too: human vision distinguishes shapes and details mainly via lightness contrast.