I have nothing against freemium model but transport yourself back say five years ago and look at the blogging landscape. You had Six Apart with outright freemium model, you had Blogger with totally free model backed by giant Google and its bureaucracy and you had WordPress, an underdog with the cleanest UI, with the combination of above two. What differed between Six Apart and WordPress was WordPress competing head to head with Six Apart in blogging software market (remember the tussles with Matt and that guy who used to head Six Apart?) but Automattic taking lions share of free users at WordPress.com (Six Apart didn't have a free user base and their Vox experiment failed).
Now transport yourself 2 years ago and we see WordPress standing alone in the blogging software market - in fact, I would say they are standing way ahead of anyone in terms of new website creation market as most are utilizing WordPress CMS. Here, we now see WordPress slowly tightening up their free model (Six Apart is no longer in the picture and Blogger was never a big concern irrespective of Google as a giant in the background).
While the so-called present day freemium model develops across the board, the micro-blogging/social world takes shape and Tumblr/Posterous appears on the scene. WordPress.com's free users now become fair game for all sorts of experiments (remember the Like button fiasco?). The free users of WordPress.com are now the guinea-pig, and the semi-serious/serious bloggers are now struggling to cough up $$ here at WordPress.com for one paid upgrade or another to sustain their long standing relationship. They now have a choice to continue here or they host their own at WordPress.org (we will help you transfer for a fee, yes!).
Nothing wrong with such evolution of all things internet, but this changing landscape is something to ponder about.