It doesn’t matter where accessibility is located within an organization. It could be part of IT, QA, Design, or IDEA. The important thing is that the buck stop somewhere to make the final call.
The accessibility team can’t say “we have a WCAG violation,”and then another team kick it back saying “that’s how it is supposed to behave.” With distributed responsibility, when everybody is responsible, nobody is responsible.
In a mature accessibility organization, there is some flexibility in how to implement a solution, but no ability for IT or design teams to say “we’re not going to fix that WCAG violation”
alt; SpongeBob badminton meme. SpongeBob is labeled accessibility and is getting batted back-and-forth over a badminton nets net by two burly lifeguards. Text at the bottom says when no one takes responsibility.