There are SEVEN brothers. All of them have trained for it, but FOUR of them opted out of persuing an elite running career.
So you can all rest assured Jacob is doing this all-in thing voluntarily - it's not like he doesn't have role models for the alternative, he's got several in his own family.
Someone needs to translate Gert's book to English. If you want something possibly controversial here's the thing (at least by Scandinavian standards): He writes that he'd throw anyone of his sons out of his house and probably cut all ties with them if he ever found out he's been cheating on his woman or had a divorce from his wife. In his opinion all men in his family should marry for life, that's non-negotiable.