The United States has a curious habit of inventing its own sports
sometimes this is really interesting and cool Sometimes this is a major handicap
In the sport of kickboxing it has been a devastating decision
Throughout the world kickboxing has a handful of primary Styles but they all revolve around the traditional King from Southeast Asia....
Muay Thai
Instead of adopting the internationally accepted styles America took kickboxing and created its own unique particular style
Sportsman often focus on extrinsic matters. What matters is the art & quality of the training.
I took the third video because it captures these two governing dynamics extremely well.
Kickboxing in the USA? is a rather generic kicking & punching art. Grew out of boxing with presumably the karate's kicking influence, without the formal grounding in either. Hence a weaker art in principle. Hence more dependent upon the athletic capability of the practitioner compared relative to other arts.
Muay Thai is most certainly grounded in certain principles, including developing great strength in the body to throw extremely powerful strike, especially the kicks. Boxing in comparison, focuses more on technicals of out-landing punches on the opponent. Muay Thai Thailand is a pure art.
It's not surprising then, to see the outcome here. We have an highly talented athlete in the American kickboxer, who excels at this craft. For all his well rounded and well demonstrated kickboxing style, however, he is neither as powerful or as tactically savvy as the more traditional Muay Thai fighter. Consequently, it's ultimately a losing battle.
The American kickboxer also displays the inherent weakness in his American version of the kickboxing style. Attempts to throw accurate technique often have no appreciable impact on the tougher Muay Thai opponent. The American kickboxer does not fare the same.
Secondly, the American kickboxer's typical hands up guard defense is often ineffective. Especially at crucial moments which is all it takes. The hands up guard is fraught with openings depending on the flow of the action. And is so exploited by the Muay Thai stylist here.
Thirdly, the American kickboxers foot work presumes a certain boxing-like range, which doesn't match with the constant stalking approach by the Muay Thai traditionalist. The American struggles to regain his range.
Finally, the American kickboxer's hands reflect the usual bagwork, mitt, and sparring practice in stark contrast to the carefully calculated moves by his well-honed traditionalist opponent. A ring sense deficient.
All this goes to show that a typical American Kick-boxing regimen does not impart the capability of a high class Muay Thai stylist who is more grounded on bedrock traditional stylistic principles, no matter the very high athleticism of the American.
The fight ends with the American getting clocked then rocked, then backed into the corner & pummeled as he frantically covers and swings and covers and swings only hastening his demise. Classic sport fighter destroyed by traditionalist.
In line w OP's thesis.