Did 2.1 break my page archive?

Yes, it did.
https://www.transycan.net/blogtest/2007/01/23/how-pages-are-different-in-wp-21/

And oh, the subpages containing the articles are still there. They just don’t appear in the list on the parent page (which serves as the article archive main page).

Ah, thanks! That was simple, but I’ll post it here if someone else has the same problem. All I had to do was change this in the parent Page template, from:

WHERE post_status = 'static'

to

WHERE post_type = 'page'

You may want to read the Update, too ??
(since 2.1. Pages also can have published or draft status!)