“Over the course of the next several months, we’ll be migrating the underlying technical implementation of Docs from the current HTML-based rendering approach to a canvas-based approach to improve performance and improve consistency in how content appears across different platforms.”
Google is turning documents into pixels painted on a canvas. Every extension that reads the page breaks, and so does every tool that isn’t Google’s. Screen readers needed a follow-up update to the post. The performance excuse is real. So is the side effect of locking everyone else out of the text.