I believe he realized that is nearly impossible to produce a championship level talent every year by "gambling" on a great QB. They are hard to find and if really good only play 2yrs. It appears that he altered his strategy 8yrs back now to get the BEST OL and layer that depth if possible. OL don't generally leave early. OLs that are good play 2-3yrs (not as much tour over at QB). This new strategy allows Saban to plug any decent QB in each year (heck he could probably do it each game). The bonus he saw was the protection you get from a GREAT OL and the amount of time you get to make the correct decision. It appears this strategy works 5 out of 9 times!!! given his history of NC. The college game has ALWAYS depended upon having a great QB. Every single great team from the past has had an unbelievable QB at the helm. The Alabama teams that won NCs have not had good QB (avg at best).