2.3% of the population have a visual impairment (https://ux.stackexchange.com/questions/57340/percentage-of-s...).

But because conversion rates are typically low and because of how the math works out for a funnel product, there's a larger business impact depending on which 2.3% is cut out. (Ignoring the negative business impact of being non inclusive/a11y)

12% vs. 10% is a 20% decrease in performance.

100% vs. 98% is a 2% decrease in performance.

I'm not arguing against a11y. I'm just saying, that's why ADA exists. It's not in the business interest without the law. Also it's just good ethics to be accessible.