Now check the cost difference between a T-34/85 with a PzIV and a Sherman with a Panther. Actually if one's opponent is spamming allied mediums making Panther is not the best response, one would probably do better making stugs or PzIVs.
You didnt stop at premiums, you said heavies and super heavies make p4 obselete. Check that cost difference, thats a lot more extreme than panther vs medium
The panther is absolutely relevant, its literally one of the things the thread is about. You can say its a different type of unit, but it still outclasses allied mediums. Super heavies are a different type of unit too...
Bottom line is that PzIV is not a very good investment because it has a high cost for the window of opportunity it has. Which has become smaller with the changes to Super heavies.
Bottom line is the same is true for the stock allied mediums. The window for all medium tanks became shorter with super heavy change, this is not just ostheer