Scott Rafer, in the first comment, summarizes what I immediately thought - even if the other 90% of the advertising moves to the web, it doesn't mean that all those dollars will move to the web. It'll be used to cut cots.
Only if it doesn't result in a competitive disadvantage. If ad spending is effective it will get done, because those who do it take market share from those who don't.
Only if it turns out that ad spending on the web is less effective overall than ad spending on traditional media the ad pie will shrink.
There are no indications that this is actually the case though. The interactivity on the web opens so much potential for much more engaging types of advertising. I hate it, but I'm afraid it's only going to increase.
