Google SERP Change - Is 7 better than 10?

The Cause for the algorithm change is still up for debate.  Many have suggested that it is due to Google enforcing more variety of it's results.  Let's say for example that "Acme's Anvil Corporation" has 2 pages of it's website indexed on page one of google for the search query "acme anvil".  The home page is one result, and the anvil section of the store is the 2nd result indexed.  It's possible that google is removing this 2nd indexed page from the first page of the search engine results for that query, and making room for someone else, theoraetically causing a larger variety of results on page one as opposed to a page dominated with indexed pages from the same company.  Another possibility is that Google is combining that result into one result with the "site links" shown below.  This has been seen fairly often on SERP's with 7 results, and is mainly noted when a branded search is performed.

Google making it more necessary to join google Adwords?

Could this possibly be Google's way of making it more and more necessary to join the Google Adword's game?  If it's only limiting SERP's to 7 a page 18%-20% of the time, will it really make that big of a difference?  I think this will cause many webmasters to rethink their SEO strategies as far as whether or not to supplement organic search engine results with ppc (Pay Per Click)  If Google is in fact combining "established organic page one real estate" having an ad displayed to control at least 20% (2 out of 10: 3 sponsored results + 7 organic) of the market share of results for that search query seems to be the next logical step for webmasters to take.