The further someone is removed from actually using a digital product, the less they understand its accessibility problems (even if they have the technical knowledge).
For example, when analysing or testing accessibility in existing projects, a person who uses assistive technology daily understands the experience intimately. Someone who works with such users occasionally grasps some aspects. And someone unfamiliar with them is entirely in the dark.
The disconnect is even bigger when we consider that people with different disabilities use assistive technology in different ways.
This also happens when creating a project. For example, someone working on the frontend of a project brings deeper knowledge of implementation and its implications than a project manager.
Your perception of accessibility degrades the further you distance yourself from use and development, because you miss more problems.
This explains why procurement and requirements definition are particularly difficult to address, as these decisions are made far from the actual use.
Understanding accessibility requires direct exposure. See how the website operates in different browsers and conditions. Try to navigate using only the keyboard. Experience first-hand how screen readers work.
If accessibility remains theoretical, or if we haven't felt its friction firsthand, we build blindly. Even if we have the knowledge, we lack awareness of what we don't know.