Do you really want to go back to the days of our starters only striking out two batters? Also, Lannan only has 29 games out of 128 where he gave up one run or fewer while going 6 innings or more, so that would be more "best case" John Lannan.
He had a quality start 70 out of 128 times or 55% which is above the league average
btw, the average NL starter from 08-11 accomplished the feat you stated 25.6% of the time which is lower than Lannan's
