Fighting games are a notoriously difficult field for those who want to be pro players. If you want to win any events, you better put down some serious hours into these games, and that alone is not enough. You need to develop your execution skills, you need serious mental fortitude, and you simply must develop analytical skills.
That alone is a lot, and therein lies the problem for many pros, because the amount of time you put into fighting games, and the effort it takes to defeat other top players is rarely reflected in the earnings that you can expect from the tournaments.
For this reason, it's even more impressive when someone does make an effort to be a full-time pro and succeeds, and Nephew seems like he's committed to this admirable goal.