Reality Check for Online Advertising?

According to a Mckinsey Article:

Internet advertising has recaptured the imagination of marketers.

Yet recent McKinsey research finds that supply bottlenecks could limit the pace of online ad growth and drive prices higher. Moreover, a dearth of ad agencies that can manage both traditional and digital campaigns could further slow the shift in spending to online ads.

Over time, inventory levels will increase, and marketers will be able to shift larger portions of their budgets online. Until then, marketers will have to manage a broad and rapidly changing array of media vehicle

Interesting read (registration required). The article talks about demand outstripping supply over the next 24 months (US data). I cant see this happening over the next 6-9 month horizon but as the ability to optimise inventory improves I can see inventory being optimised more efficiently and the effective CPM rising sharply, this in turn can catapult demand. This is already happening with the rise of the adnetworks. All we need is a mass supplier to do this better (Google Adsense maybe?).