Typical users don’t set ALT tags, roles or aria attributes. Majority of images uploaded through media library are used in posts/pages and are not decorative.
If we do want to prompt user to add ALT tag, we can also give them an option to check “Decorative use only”, which would set appropriate role/aria.
From WebAIM on alt text:
“Every image must have an alt attribute. This is a requirement of HTML standard (with perhaps a few exceptions in HTML5). Images without an alt attribute are likely inaccessible. In some cases, images may be given an empty or null alt attribute (e.g., alt=”")."
If image has an empty alt tag, screen readers ignore it completely. If image doesn’t have an alt tag attribute, screen reader will say “image”.
Again, it’s not perfect but for majority of the cases it will be an improvement. Far better than to do nothing as it is now in WordPress.
It’s similar to how WordPress enables automatic updates for minor versions for all to try and accommodate typical users who don’t update. But, if you know what you’re doing you can customize automatic updates to turn them off or change how it behaves.
~ posted by Viktor Nagornyy