A typical model might describe stages such as: unaware (no accessibility practice at all), reactive (fixing issues only after a complaint or audit), defined (a documented policy and some testing exist), integrated (accessibility is built into design and development workflows by default), and optimized (accessibility is actively measured, monitored, and continuously improved).
Maturity models are useful for benchmarking progress over time and for communicating accessibility investment to leadership in terms of organizational capability, not just a single audit’s pass or fail score at one point in time.