The business case for accessibility extends well beyond legal risk avoidance: the World Health Organization estimates roughly 1.3 billion people, about 16 percent of the global population, live with a significant disability, representing substantial spending power that an inaccessible site simply cannot capture. Accessible sites also tend to perform better on core SEO fundamentals, since many WCAG practices (semantic structure, meaningful alt text, clear headings) directly overlap with what search engines reward.
Quantifying ROI precisely is genuinely difficult since a lawsuit avoided or a customer retained rarely shows up as a clean line item, which is part of why accessibility investment is still sometimes underprioritized relative to its real value.