These sites will be built with Ajax, Flash and other interactive technologies that allow the user to conduct affairs all within a single web page – like Gmail or the Google Reader. This eliminates the need to click from one page to another. The widgetization of the web will only accelerate this.
This is absolutely not the case at all. All of the major analytics users have means of integrating page views via client-side scripting. In fact, I think the analytics industry has been ahead of the curve, having moved from log-parsing to client-side scripting years ago. Now, they offer the ability to post variables back to the analytics engine that accurately identify client interactions.
I will state that the definition of a ‘page' will change. A page can be a portion of a page, a widget, a feed, etc. Interaction from a client is still accurately depicted this way, though. Where a client would click a link and have a new page show up before, now they click a link and the content changed. This is still interaction and can be measured effectively.
RSS consumption is accurately measured through applications like Feedburner, which redirect your feed through their engine for measurement. Widgets are developing their own Analytics engines, as seen here with MuseStorm. Flash can take advantage of any/all of these interactions with analytics firms.
Case in point: Payraise Calculator (one of my sites), is built with Ajax. When a user clicks “Calculate” and I load the completed calculation in the original page, I pass on that information to Google Analytics. When I view Google Analytics, I can accurately see how many people visited the site, as well as how many ‘page views' were executed. (I don't actually capture the calculation, though!).
My prediction? By 2010, Analytics firms will accurately depict pageviews for any common or uncommon usage of your content or site… be it Flash, Ajax, or Widgets. The clock is ticking on these third-party applications that do this now. What will change is our understanding of what a ‘page view' actually is. While deemed as the entire browser page before, it's now going to be a measurement of interaction with a web site. However, that interaction is no less important to the marketer or advertiser.
With all due respect, Steve, I'll gladly bet you a nice dinner over our difference in opinion!