Because they're still annoying. No one will break the banner ad model until someone does successful micropayments for things like news stories, I believe, and this might not happen until things like newspapers are gone. That's scheduled for the day after the Cubs win the World Series. It's something I want to see, so long as the information is portable in some fashion. It's not so much that I have against the banner ads, as mentioned in the earlier thread on this topic , but it's the size and annoyance factor.
Most people are at the point at which they ignore banner ads.
The size of the large internal page Flash ads does detract from the main content. On the first day many of these ads were broken, which meant users got a huge block o'nothing - which could be worse. I maintain that these things are wholly annoying and ridiculously oversized. Say, here's a thought. I don't really have any problem with the size of the ads, or the fact that they're Flash.