Two things can be true at once. You can be good and lucky at the same time. It can be true that Liverpool have been the best team in England this season and that they have been lucky. Liverpool, for instance, have gained 10 points in the last 10 minutes? Good fitness? Yes! Luck? Also yes! Winning that many points at the end of games isn't going to be sustainable long term, however good your fitness is.
Look at injuries. Liverpool's best players are Mane, Salah, Firmino, TAA, VVD, Robertson, Allisson and maybe Jordan Henderson. Only Alisson has missed significant games in the Premier League.
Our best players are probably Rashford, Martial, Fred, McTominay, Pogba, De Gea and Maguire. 4 of them (which includes our 3 best attacking players) have or will miss significant time this season. Obviously, decisions made by the club/Ole have compounded these injuries in Rashford's and Pogba's cases. So it isn't just luck, but it has played a factor.
For anyone saying I'm discrediting Liverpool, if you read the whole post I acknowledged we could never beat this Liverpool team playing as they are. None of Ferguson's teams would have got close to this lot (luck or not).