I think internal organizations of employees of various shapes (unions, affinity groups, "employee resource groups") can be useful for diversity and inclusion issues. But you also need budgets and power and integration with other departments. HR needs to care about non-discriminatory hiring practices in a first-class way. Legal needs to see ensuring good-faith legal compliance with the requirements of the ADA before anyone brings a lawsuit as part of their mandate.

Anonymous, third-party outlets for complaints like Blind can also likely be useful. Even at companies that never punish anyone for criticizing the company, participation rates in internal surveys are typically atrociously low, and people stop speaking up even informally if it's clear to them that nobody actually acts on employee feedback. Most companies probably perceive such channels of communication as threats, though.

Idk about audits. I worry that it's easy for them to become their own circus and overhead without materially improving things. But you may be right.