When I was in college, I worked as a line cook at McDonald's in the US of A on a work and travel visa. I hated that job.
Line cooks flip burgers, toast buns and keep up with a constant stream of orders. The only way to survive it is to only do the thing in front of you. If you're toasting buns, that's all you do. You don't know what the guy behind you is doing. And frankly you don't care.
You don't know the whole process and you don't own it either. You own a piece of it. Your piece. It's the pioneered way McDonald's can deliver every order in 90 seconds or less.
That sounds fine. At least until quality slips. And trust me, it does! And then nobody knows where it went wrong. Nobody feels responsible for it either. Often, problems show up between the steps. And these problems never really get addressed.
You can't improve a process you're only vaguely familiar with. Real improvement happens only when the team owns the entire process.
And I rarely see this happening with accessibility either.
When a designer makes sure the colours look good and a developer only builds what's in front of them, nobody owns the experience of someone with a screen reader or a keyboard.
The accessibility issues that matter most don't live in any one person's lane. They live in the gaps. They live in the hand-offs between those lanes. And nobody catches them because nobody sees the whole thing.
When something breaks, it's hard to know where it went wrong. Or who's responsible for fixing it.
Accessibility only improves when someone actually owns it end to end. Not a checklist. Not a plugin. A person, or a team, that sees the whole sandwich.