how is this an endgame study at all when even a 1500 rated player like me knows how to easily win as white
How does white win this endgame?
You just push the pawn up no?
Lets see. 1.g6+ Kh8, then what? 2.Kf7 ios stalemate. 2.g7+ Kg8 3.Kg6 stalemate. Any other king move and Black plays Kg7 and there's no way for White to make any progress

This is winning for white because of an important endgame rule to remember (and practice):
"a pawn on the fifth rank wins with the king in front of it."
With the exception of when the pawn is a rook pawn, if king on the 6th and pawn on the fifth always beats a lone king.
This is way too general to be true. In this example, If white is Ke6 and g6, black is Kg7, it's a draw.