Fair points. I just tend to roll my eyes and discount anything that purports to value "playoff experience!" really highly, when presented as some sort of analysis. There's a first time for everything and everyone. Nobody thought Tatum would be a major contributor as a rookie to a 2017-18 team that had traded away Isaiah Thomas and then lost Hayward (early) and Kyrie Irving (late) to injury, but he made a lot of things happen in the playoffs in the course of bringing us to Game 7 of the ECF. Other than the coaching staff knowing how to prepare a team and make adjustments, I have a hard time imagining the mechanism by which "experience!" is something you need to first accumulate before seeing playoff success. Young Lebron hit the ground running: he won a series the first time he made the playoffs despite his team being awful (2005-06, his 3rd year), won 3 series and went to the Finals the next year (2006-07), and then was famously only stopped by the Celtics juggernaut in 2007-08.
You can cut playoff results any way you like to suit a narrative. Insert the XKCD cartoon all you like. But people who think experience is some sort of leveling-up grinding that players need to do like an RPG character before they're ready to be a real contender seems overstated, here and everywhere it crops up. They'll point at things like Jordan's first 6 years, and ignore Tim Duncan surging to immediate success; they'll point at Tatum's "failure to win a title" thus far but ignore the team and league context that let Larry Bird jump straight into contention his rookie year and win it all his sophomore year. Did Paul Pierce not have enough playoff games under his belt before 2007? No, it was the arrival of future HOF teammates. But then again in his very first playoff run, in 2001-02, he and 'Toine charged straight to the ECF, with nary a playoff game betwixt them - no experienced required! If you're prepared to define "playoff success" in whatever way suits your narrative, there will be numbers for you to find, ways to cut things to suggest your'e right. I'm just not sure the entire topic, writ large, is a useful way to view the likelihood of OKC 23-24 (or anyone) winning a series or multiple series.
I personally find the matchup-based way of viewing things to be far more enlightening, because people can post clips and show how certain things Team X or Player Y like to do can be taken away by Matchup or Tactic Z (or that the opponent has no way to stop it, and that might prove decisive). For one thing, it makes what happens in the game make more sense to an informed viewer. But more importantly, it has a discernible mechanism of action - it's pointing to specific things the players are doing, or trying to do, or can't do, or need to respond to / adjust to, that will ultimately determining the outcome. Citing "playoff experience!" as some sort of distilled oracle of playoff results seems to be lacking any cohesive story for why it's determinative (again, other than coaching preparedness - but even still, you'd think that would be fairly uniform around the NBA). And I suspect if we were to agree on some sort of definition for what is considered sufficient playoff experience - "now, young padawan, you have reached an age where your fortunes will be determined on your and your team's talent alone, and not these artificial shackles of ignorance that have held you back!" - and we went out and crunched the data, I bet the correlation to actual playoff results would be really low. Relative to basic things like team winning %, head-to-head during the season, injury impact, etc, nevermind more advanced things around matchups and play types. I can't prove that without a ton of work, of course, and I imagine there's existing research which would either confirm or blow up my hypothesis. But that's my thinking, that's why I'm skeptical that this thin-slicing around "# of playoff games played" has some outsized predictive value.