Great article!

What I love about default themes is that, although they support a broad range of languages, browsers and audiences, they are mostly so light, without fancy scripts and a giant amount of CSS. This is very true for Twenty Nineteen and Twenty Twenty-One. This makes them extendable (as a parent theme) without having to remove stuff you don't need. They are (and should be) like WordPress itself. :-)

I agree that with more time they could be even better, and groundbreaking perhaps. This year, we could be building the theme that becomes the standard for Full Site Editing. That needs time and testing. So when are we starting? :-)