Of course not, but the point was about where the start of the downfall began.
Here is crude way to look at the trend:
Winning % changes:
-.148 '18>'19
-.119 '19>'20
+.168 '20>'21
-.087 '21>'22
-.000 '22>'23
By far, the biggest drop was from '18 to '19, and we all realize the high of 2018 was astounding, and the 84 win 2019 season was second only to 2021 since 2018. Still, it was a clear heavy decline, and DD or no DD, the drop in 2020 was written in stone, once the budget was set so low.
DD might have found a way to keep Betts, but I doubt it. Word was, he almost traded him in the summer of 2019. Had he found a way to keep him, it could only have happened, if he traded 2-3 from Bogey, Nate JD and or Sale. In hindsight, that would have been better, but we'd still have sucked in 2020 with DD, too.
Could DD have cobbled together a team like 2021? I won't go there. Too many variables involved.