broad bush. There are people all the time that luck into things and luck out of things.

Sometimes people include kickers in their leagues. I hate have kickers in fantasy, but it's a thing, so I go along with it. I lost in week 1 to a guy in a league because Jake Moody scored like a million points. Sorry, but there is no way to predict scoring for kickers with a lot of accuracy. Kicker scoring is mostly luck.

Another luck aspect is in game injuries. I've had teams this year with Kupp and Rice. Both pacing well to score a lot of points, but it's hard to win a week when someone you expect to put up 15-20 points gets you 5. Or 0.

I don't think luck is generally the reason you win fantasy football, but it can be why you lose. I play a lot. More than I should. I have awesome looking teams that have bad-lucked into bad starts, but I have crappy teams that are winning. It happens all the time. Sometimes you score the second least points in your league in a week, but your opponent scores the least points. I don't think it's all luck. If I did I wouldn't play, but luck plays a huge role in fantasy.