Dries, also, said that releasing drupal 6 without drupal.org being updated to it was a mistake he doesn't want to see happen again.
Why it's happen ? Because big missing, "Views, OG, Panels etc...etc...", because backward compatibility API doesn't exists.
Views 2 (in Drupal 6) isn't compatable with Views 1 (in 5.x). A 'backwards compatability API' would have had zero effect, possibly a negative effect on the Views upgrade process. Organic Groups AND Panels both rely on Views - so could only be updated fully once Views was at release candidate stage. I really wish people would familarise themselves with the issues at hand before mouthing off on this list about "we need to do this [useless thing which would have zero effect]". Even a tiny bit of research would show what the issues are, and it's not API changes in core - it's manpower helping out the commonly used modules to get upgraded. If you want to see contrib modules ready when Drupal 7 is, you can start now by providing and/or testing patches for your favourite modules to get them upgraded. There are also modules with development versions or even beta releases for Drupal 7 listed here - http://drupal.org/project/modules?filters=drupal_core:103&solrsort=title_sor... again I'm sure their maintainers wouldn't turn down patches when there's API changes in HEAD. Nat