Everybody cites "81 wins" as if it's the definitive and precise mathematical measure of team quality, but let's face it -- there are different ways to get to 81 wins. They were 5 games over and very much in the race going into that September Cleveland series, and frankly took their foot off the gas for several weeks once they lost that first Cleveland series game in a heartbreaker. They were in free-fall for a while after they realized they were out of it. They were probably an 85-win team that fell to .500. A meaningless and negligible difference, really, but then so is the difference between 81 and 83.5. 83.5 seems reasonable.
As a sidenote, I love threads like this where neutral, outside reality creeps in to the Soxtalk doom chamber for a moment. The cognitive dissonance can be fascinating to watch. I swear, we could be heading into the ALCS next year and somebody would post that "the people celebrating the ALCS are missing the real point, which is that Rick Hahn failed to sign Zach Wheeler in the 2019 offseason and..."