These are TV shows with prize money for the winner. For the particular show, they are hardly informed in advance exactly what competitions there will be, but considering all the shows over the years, anyone who comes to the casting is aware that they need to have strength endurance, speed and many other qualities, including brains, in order to beat. This has been the case in previous shows of this game, and perhaps some prepare in advance before appearing for casting, but hardly have much time to do so. And they don't know if they will be approved to participate in the show. This show lasted for several months and the winner had about 25 victories in direct fights with other opponents, which is an indication that the victories were not accidental.
By the way, there were a lot of guys with bodies like crossfitters who obviously train hard, but they were eliminated. One of the finalists who came in third place was about 40 years old /now I saw in the reference, he was 38 during the show/ and at the end he said that he proved to himself and the viewers that you don't need to be an athlete, going to the gym or giving a lot of importance to sports, but when you have the will and don't give up, you can go far in such competitions and beat competitors in exactly what they think they are strong in.
Otherwise, I agree that it all depends on what your goal is. But most people are mistaken that if they go to the gym and lift heavy barbells, dumbbells and do exercises on machines and build muscle, it will give them an advantage over weaker opponents especially in competitions where strength is required - lifting, carrying, pushing, running, swimming, throwing. Only they don't take into account one basic fact - you have to be able to do it for a long time.
I've had my suspicions that if a person who only does resistance training, but doesn't train their endurance, is very likely to become even weaker in that respect over time than someone who doesn't exercise at all. There have been many instances in my life where various muscular guys have been asked to help move heavier furniture and the like, where they have tired much faster than much thinner and older people who don't do any sports.
But let me not dilute the topic further, so as not to offend its author