Nobody said they are the same!
The important question is whether the two different game environments have a non-linear impact on different player archetypes.
One analogy would be say you trying to get laid in Manhattan vs Tuscaloosa. Very different dating environments but you are still striking out in both places, 100% of the time. Some dude who is a solid Alabama 7 might wheel in Tuscaloosa but never touch a girl in New York. So you suck everywhere but he only sucks in Manhattan.
We already know that elite relievers can be more valuable in the playoffs, because they can have a bigger impact; managers will let them pitch every game, or pitch 2 innings, and generally pitch MORE than they do in the regular season.
We already know that elite SP can be more valuable in the playoffs because they can start more frequently.
There is some continued discussion on whether or not high contact hitters are more valuable in the playoffs. This is probably because there is a higher portion of elite pitching, so being able to just put the ball in play and not strikeout could be worth something. I have heard some debate on this. Some nerds agree, some do not.