Accessibility is everyone's responsibility
Boy, that sounds good! It's true, sure.
It also causes a lot of rework because when everyone owns accessibility, it's easy for nobody to own the decision that matters.
It makes it easy for product to assume the team will raise risks, design to assume the component library handles behaviour and engineering to assume that design will specify anything unusual.
Then an issue appears late, when everything's more expensive to fix.
It didn't happen because everybody ignored accessibility. On the contrary. Everyone did their job and the work still failed because the decision had no owner.
If you think, oh, I can fix this by making one person "the accessibility person." That'll show everyone!
You just created a bottleneck. Now everyone relaxes and waits for review. All that knowledge stays trapped in one's head and delivery will be slow whenever that person is busy, off sick or trying to have a holiday.
What you need is shared responsibility and clear decision ownership.
Product owns risk and acceptance. Design owns intended behaviour. Engineering owns implementation. QA owns verification.
That means Product decides what must work and what blocks release. Design shows how the experience should behave. Engineering raises gaps before guessing. QA checks against agreed expectations instead of inventing them at the end.
Who owns the accessibility decisions on your team?