skiing is not based around competition, especially freeskiing, the average pro skier spends most of their time developing in skiing, fucking around for the most part. then maybe gets serious about competing, and trains a lot learning new tricks enters a couple competitions to begin with. and by the time they are x games material, their season still is maybe 80% competing, 20% just skiing/having fun.
racing, from the day you start, you are competing, and unlike skiing you're not by yourself, your racing against your competitors at the same time. and from the start, even 10 year olds in karts. the competition is very tough, just to make it into the top level of motorsports, nascar, indycar, f1 etc... you really have to be one of if not the best from the moment you start and through each step of the ladder. then you may be good enough to even compete in the top level. what it takes to win at that level is insane.
skiing would still be skiing without the competition, its more about pushing yourself than beating the next guy. racing would be nothing if it werent for the competition, thats all its about from the moment you start. not saying one is better than the other. they both have their highs and lows. the competition is one of racings highs.