Do you have any data to back up your second point? I know dozens of people that have made careers out of passions that they discovered in high school and college. And those are only the people that I've asked about it.

But we could expand a little bit and make your claim more likely to be true, and also more reasonable. For example, if Jimmy loves playing the guitar, he could try to form a rock band and get successful enough to make a living touring. That's kind of hard. Possible but the odds are against him. So he might try that and later transition to some other job that's still in entertainment. This example, and generally the shift from a single job to something else that's related to it, is something that young people should expect. Focusing too much on one area could be a weakness if you have to change jobs later. And in general, the majority of workers will make major changes to their careers at least once in their lives.