Are web browsers not accessible by default? If you make everything out of the core primitives they provide: lists, paragraphs, buttons, forms, etc, a screen reader will have no problem, and reader mode can let the user tweak it. It's only when people reconstruct primitives that assistive technology breaks. I don't see how you can fix that at the browser level except by taking away all the toys and breaking 99% of the web.
Reader mode will help with some disabilities but not others.
> It's only when people reconstruct primitives that assistive technology breaks.
I like using the platform too, but users don't use primitives - they interact with higher level elements like carousels, profile pictures, comment boxes, and most new UI elements do not have accessibility industry ARIA role.
