I feel like baseball stats and baseball history are already completely flexible, we just treat them as sacrosanct. 154-game schedules, different ballparks, different balls, mound height, etc. If they changed the wins the official record book would not be adjusted retroactively. We would just understand - as we already do now - that wins were different then.
That said, all the articles about what the new win criteria would mean for historical stats would be thoroughly entertaining! I think the five-inning rule would remain loosely in place, you should just add scorer discretion for starts of less than five, just as they have a lot of discretion for awarding wins after that point. Including awarding a win to an opener if the score truly suggested that (I assume now that is impossible since the opener is defined as a starter who didn't go five).
I think it's just a reaction to the playoffs and the bullpen-happy managing style in general. Yeah, starters are bigger stars but they also get paid more, not every one likes that. But having introduced the three-batter rule and the pitch clock, one less pitching change per game would speed things up even more.
Except, of course, they could have just left rosters at 25. Seems like they didn't anticipate that in the long run nearly every team would use that extra spot on a pitcher, especially once the NL lost the DH.
As for as the "follow the money" thought, this seems of a piece with the 100-win teams not making the World Series. The playoff format and the bullpen-happy, analytics-driven management style still favors small market teams in theory. Even if the Phillies were one of the so-called underdogs. They had an $18 million fourth starter who didn't pitch in the playoffs and five relievers with closing experience who'd all make $8-10 million or more as free agents (as the two who were did). Yeah the Phillies had Jeff Hoffman but a team like Tampa is always trying to have five Jeff Hoffmans.
Speaking of Tampa (and perhaps case in point): their most-used catcher this season was Christian Bethancourt?