Elder-Basilisk said:
Historically, when plate armors became available the knightly class abandoned scale mail. When full plate armors became available, they abandoned the chain and plate armors. Why should PCs not do the same?
Historical (i.e. real world) comparisons are often very misleading.
In reality, knights rarely wore the heaviest armor available, even on the battlefield.
It was dependent on their job du jour.
The heaviest armor was typically only worn in calvary divisions and then, only during a specific time of day when they expected to do a charge. If they were not fighting, they would either stay mounted, or they would get out of the armor.
PCs, on the other hand, can wear the heaviest of armor at all times (except sleeping). It matters not that in reality, walking in Full Plate Mail on a summers day for an extended period of time could give you heat stroke.
In real life, a typically fit (but not extremely athletic) person could not even walk through a cave complex in medium armor with associated gear for two hours, let alone adventuring for an entire day and including combats within that timeframe. But in the game, your physical attributes do not matter with regard to how long you can wear and use armor and carry equipment as long as the weight is within your carrying capacity. The game mechanics are not really that realistic in this regard.