High School Chess is essentially the desire to die in a sea of crazy tactical complications. This we all know, (and many of us have experienced).
So What ?? Most of them just burn out after reaching USCF 1800.
Conversely, USCF 1800+ is the 90th percentile, and that top 10 percent accounts for fully 50 percent of the games played.
They are very busy fellows. And most of them know lots of endgame theory. Granted, some a very tactical at Game in 5 hours. But again, so what??
Endgame knowledge adds pleasure to the game, and affords you the capability to play (very) quickly. Usually a 5 second bonus is all you need, to reach the end of the game "on the board," not "on the clock."
It's so easy to sidestep nearly everyone's opening prep by playing a universal opening. After 20 move pairs, which you typically know better than your opponent, the position is usually level, unless someone drops material.
Tactical and endgame knowledge (at any speed) makes playing much easier, and faster. It's the measure of stronger players. Take the hint.