Thanks, Doug!

I didn't advocate for a button disappearing and reappearing while the user is on the page. For Solution 1, I stated that you should only hide the button if it will never show as long as the user is on the page.

Keeping a submit button disabled until all forms have valid entries doesn't inform an AT user that it's available. So if they enter invalid or incomplete data (but think they have entered it correctly), they'll be searching for the disabled button and never find it.

Regardless, it appears that you've read the articles. Even if you disagree with my conclusions, I appreciate you taking the time to go through these articles instead of simply reading the title and voicing your disagreement right away.

So, I thank you (sincerely)!