If you built something like a Flak ht with Okw, a pershing deploying at the same time as a p4 represents about a ~40 fuel lead, gg doesn't really seem reasonable.
In particular for axis I think the P4 has trouble scaling against Heavies with it's low pen so it's tough to justify purchasing when you know a heavy is in the opponents loadout.
Often better to just build light vehicles, stall and then callin your own heavy. There's just not as much space for mediums to be effective when they don't scale very well against them. It's a meta issue as much as it is a snowballing one with the current timing.
But that's an issue every medium tank faces. Risk building a Sherman or Cromwell over Jackson or Firefly when you know the enemy has Panther or Tiger in a few minutes?