I've never used a replica jersey in anger, but I tried one on. The fabrics weren't as good, and the cut was looser. Nowhere near as good as a PT jersey IMHO.
The fabrics are never going to be as good when the replica is 60% of the price of PT. Both jerseys have been fitted on the exact same human. The difference in size is negligible/in your minds.
Possibly, you may be right. All I know is that when I tried on the replica jersey the cut felt more like a Classic jersey than the PT one, which has noticeably tighter cut than the Classic.
I've never used a replica jersey in anger, but I tried one on. The fabrics weren't as good, and the cut was looser. Nowhere near as good as a PT jersey IMHO.