Interesting article about how, against conventional wisdom, the 2020s extra inning rule has resulted in a home field DISadvantage, and has somehow benefited the visiting teams:
https://blogs.fangraphs.com/the-math...-disadvantage/
Home teams have only won 49% of extra innings games from 2020-24, whereas they were winning 52% before that.
The author surmises that it has to do with the visiting team knowing exactly how many runs they need to prevent, and adjusting defense accordingly. They can intentionally walk more batters, play the infield and outfield very close, and aggressively pitch for strikeouts. The home team cannot do this, as there's no limit to the number of runs they can give up, so they have to play more traditional defense.
Of course, there can be an adjustment to this strategy, but it hasn't happened yet.
However, I do want to propose one other possibility -- one not considered for this article.
Is it possible that the home teams going extra innings are simply worse on average than before, and more prone to finish 9 innings tied instead of ahead? Of course, that has always been the case, but it the 2020s have seen less parity in team ability, perhaps that explains it, too.