Not enough guys have the size, physical maturity, toughness, and technique at that age. The pool is limited.
In the lighter weights, you can see many cases where pure offensive technique guys can overcome strength, and physical maturity.
At the same time, the ability to score defensively is a premium or luxury. (Great example is how Tsirstis - his ability to score off of counter is what I believe set him apart as he moved from light weight to middle weights.)
In the middle weights, it's technique, strength, and pound-for-pound nasty toughness. A balance of offensive accomplishment
and defensive ability are required. These weights can just be all out brawls and street fights. A lot of matches in the state finals where the tougher guy beat out the technique guy.
For the upper weights my theory is this:
#1 - You don't see that many kids with that size as Freshman and Sophomores. The guys that do stay in wrestling and are not lost to
football are pretty good athletes (in Sliga's case, great athletes) but not enough of them stay in the sport. So having one like
Sliga who was way more mature, better technique, wrestled year round, is rare. But 90% of the big guys he wrestles just do
not get the reps and number of year round matches to be polished and fluid like Sliga (which is also a prop to Sliga's work ethic).
#2 - Raw Strength, Maturity, and defensive ability in the upper weights can overcome a decent technique guy. These guys are
basically linebackers who wrestle. The difference is they might not have 100 moves like Sliga, but they know how to use what
they do. But the guys who have offensive skills at that weight are a premium
In Sliga's Freshman and Sophomore years, his technique got him almost all the way, but he ran into some guys (Atwood, Stevenson) who had just enough offense to score and were strong enough to counter his really good offense (he still was technically superior), and much of that was due to just 'old man strength' and brute toughness. But by his Jr. year, you saw a transformation from technique and good strength to where he was just better defensively and was just plain meaner. Don't know the guy personally but he seemed more mature, wanted to pin guys and put them away, a sense of urgency.
But if you look at guys with good technique that have been able to let their bodies grow, they do pretty good in the bigger weights if they can adjust to the strength required and had good defensive technique. Take a guy like Brian Harvey who goes from 103 to State Champ at 160. A better example is the number of college guys in the MAC who were pretty good middle weights in high school, but perhaps not top rated due to depth in the wight class. They go off to a MAC School or East Coast Conference, get huge, and are stud 184 / 197 lb'rs in the NCAA.
In college, I think he can be special because he will stay at 197 lb for years, which is rare. The cycle starts again.