Setting aside the given possibility of going to say St. Barts and giving the government a large sum of money in exchange for being allowed to become a citizen and join/form the Olympic ski team from St. Barts and also already being a world class skier, it’s never going to happen.
These days people start training or being trained for the Olympics and most other sports as young as six months old. The athletes at the Olympics at least from the major countries are the absolute elite of the elite, the .001% of the 1% in their particular sport. And yes this includes stuff like bobsled and skeleton and luge.
Then why hasn’t anyone done this? It’s not like this is a some brand new idea.
Contrary to what you claim the skill sets required have little if any overlap and require different muscle groups to be built up and used. As to the new skiing snowboarding events being new, no they aren’t. They may be new to the Olympics, but they have existed for over 30 years albeit in primitive form in the early years, as is the case with all sports. But to say that the #1 ranked downhill skier could just walk over and medal in moguls or whatever after 6 months of training is ludicrous. You literally have to relearn how to ski and your body has to learn an entire new set of muscle memories and even then you are 15-18 years behind the kids who have been doing it since they were 6 months old.