There's a thread going on at WW about how when a search engine gets successful and forgets their focus on search, a new one comes along to get back to basics. Add to that this comment in Matt Cutt's blog http://www.mattcutts.com/blog/red-herring-background/ Makes me think of how a new search engine can succeed in finding quality SERPS. They can put sites with adsense and ypn on them into a sandbox, especially when those sites only have a few internal links and adsense links (a sure sign of a site that was made solely for adsense). Sites that don't have all that will get greenlighted in the SERPS quicker. That would be an interesting twist.
At first I thought you meant that Matt Cutts made that comment (though it read a bit strange). A little more research reveals that was someone else making a comment on Matt's blog. Thing about a new search engine sandboxing sites with adsense on them, is that a lot of quality sites have asense on them too. Would be about as dumb as having a general sandbox for all new sites (oops).
Adsense is not the only fruit. There are plenty of totally spammy affiliate pages out there. Wouldn't make sense just to target those.
Content should be first by all means, but most of us do start our sites to make money from them as well as enjoy them.