I did some quick math and it's possible there is an error in here, but I took a look at how often the team with the best record in each league made/won the World Series by era. Here's what I came up with:
Pennant era (pre-1969) - Obviously, the teams with the best records made and won the Series 100% of the time.
Divisional era (1969-1993, excluding 1981) - 60% of the teams with the best record in their league made the Series, and 63% of the WS winners had their league's best record.
Wild card era (1995-2023, excluding 2020) - 36% of the teams with the best record in their league made the Series, and 39% of the WS winners had their league's best record.
It goes without saying that the more teams and rounds you throw into the playoff mix the harder it is for everyone to advance, but this illustrates how seldom the "best" team wins the WS these days. One of the things that I've always loved about baseball is having to prove yourself every day for 6 months. The current post-season tournament certainly waters down the import of that considerably.
That being said, it's not going away, so we need to figure out a way to make it happen in the post-season. As others have said, if you consistently make the post-season, the hope is that you'll eventually win it all.