Alas PH you are comparing apples and oranges. SOS is a key factor in selecting at-large bids and is a strong predictor on who gets a bid. Once the field is selected, it is not nearly as important in determining the national champion. Chapman is the only winner in the last five years that had an SOS in the top 10. Only one national champion in the last ten years won with an at-large bid (Texas-Tyler). Winning your conference is a much better predictor in determining who wins the WS, than SOS. Winning your conference bid is a lousy predictor as no teams in this category has ever been given an at-large bid 
“Alas” I’m not looking to set a comparison...more like trying to debunk the SOS as a worthwhile metric. I understood your post as suggesting that West Region teams should go to build SOS, presumably because by beating all those “better” teams (that otherwise end up with better SOS), the West Region would then achieve the SOS rating needed to qualify - not win, mind you in the playoffs...because 4 of the last 5 WS champs actually had the temerity to have low SOS.
What I am trying to do is learn why SOS continues to be used, when it may well have no correlation to getting the best at large teams. I suppose somewhere some wonk says, “we gotta have a way to compare teams mathematically and objectively”. Which seems reasonable...but baseball defies that SOS comparison and is unlike football and basketball when one considers that football plays once a week with generally static lineups, and basketball plays multiple games but also plays with static lineups. I don’t think St. John’s is going to start their left handed cornerbacks against the righty QB from Carlton and their righty corners against St. Olaf’s lefty.
Baseball lineups are not static and teams play several games a week. A different pitcher every game, a week where a team has a league series on the weekend but must play a non-league on Thursday so they staff pitch Freshmen and Sophs...SOS is a lazy man’s stat for baseball. But I read that “SOS is a key factor in selecting at large bids”. Choosing at large participants for playoff should be looking to include the best remaining teams. Based on who’s winning the WS, SOS does not appear to serve that effort very well.
