Those are issues with the CMS being used to host the blog. The blog has been around for a long time and isn't using BaseWeb.
What you're suggesting is that when someone releases a library with a commitment to accessibility, they are also responsible to reach out to some completely unrelated comms-focused team, take over their CMS workflow, rewrite it entirely with the new framework, and only then make a blog post about the thing you were trying to talk about.
Who is "you"? Me personally, the team behind BaseWeb, the comms team, Uber as a whole? Companies by definition can't "care" since they are emotionless entities, so you must mean a physical person. But physical people within a large organization might care about different things with different degrees of priority or be prevented from doing the best thing (tm) for various reasons. But we all already knew that.
No, what I'm saying is that Uber has thousands of engineers and hundreds of web projects, and it's a bit silly to suggest that if one team releases some net positive thing, the cost/time for getting every Uber property to benefit from that thing immediately is zero, and that by not doing such trivial work, Uber is a bad bad dog.
What you're suggesting is that when someone releases a library with a commitment to accessibility, they are also responsible to reach out to some completely unrelated comms-focused team, take over their CMS workflow, rewrite it entirely with the new framework, and only then make a blog post about the thing you were trying to talk about.