I’m sorry, but 99.99% is a laughable hyperbole. A huuuuge number of people have disabilities and disabilities are extremely diverse. A simple example is colour blindness. Google says 8% of men and 0.5% of women are colour blind. Video games frequently do use colour in a way that makes colour blindness a problem and colour blind modes are an accessibility option.
Google also says 15% of the world has some degree of hearing impairment. That’s admittedly biased towards seniors, but I can find numbers that say 9% of 20-39 year old Canadians have detectable hearing losses. Captions are an accessibility option.
And those are just two examples. There’s tons of disabilities out there. Even when an individual disability might only be 0.1% of the population, add them all together and there’s a substantial number of people who are left out by lack of one accessibility option or another. Aside from obvious disabilities, there’s also just general worsening of reaction times as people age.