Javy regressed in 2020. He posted an even higher 6.6 WAR in 2019 then his 6.4 in 2018. With him, Bryant still peaking, a well behaved, less distracted Russell who’d perform at a high level, especially better than Descalso and Darvish and Heyward playing up to their contracts then things might have gone differently.
It’s a matter of playing performing relative to their projections that never happened.
the bats are a mystery though. Is it the wrigley day games wearing out players by September? Cubs were able to withstand it in 2016 thanks to age and a deep bench getting the regulars needed rest if it’s indeed a culprit.