To be fair, it’s not a necessary requirement to be in elite shape to be successful in combat sports. Plenty examples exist of poorly conditioned athletes winning their fights due to disparities in skill, advantageous stylistic matchups, or just pure luck.
With that said, good conditioning solves every problem that bad conditioning creates.
One of the most important fighting attributes, if not the most, is pressure. The ability to relentlessly force your opponent to adjust to your actions can grind even the toughest opponent down over time.
Early human hunters basically just outran their prey until that prey got too exhausted to continue. This strategy allowed smaller humans to take down massive game — game that was stronger, more durable, and more deadly in close quarters.
As such, when it comes time to compete, your main focus should be on building your conditioning to elite levels. The long term process of improving your raw attributes, building your technical abilities, and improving your strategic mind never ends, but it takes a back seat to ensuring that when push comes to shove, you can keep pushing.
And fighting mirrors life. Whatever lessons we can glean from the ring or cage are often directly applicable to those challenges we face outside of it; the ability to outwork and out-pressure antagonistic forces can go a long way towards finding peace and stability.
Sometimes simply learning this lesson first hand in the microcosm of sport allows us to gain the confidence needed to apply it to those larger obstacle in our way!