Luck absolutely matters. My only issue with Pythagorean win totals is it is just based on run differential. Run differential is important but if you are losing a lot of one run games sometimes it is an indication of luck but sometimes it is an indication of having a crappy bullpen or not hitting well with runners in scoring position.

The Blue Jays in 2015 had an incredible run differential but were languishing around .500 and 8 games behind the Yankees at the trade deadline. They still went for it. Anthopolous traded the farm for Price and Tulowitzki, picked up a couple bullpen arms and Ben Revere to bolster the outfield D and give them more contact in the lineup.

They went on a incredible run at the beginning of August and won the division. Was it a reversal of fortunes or did David Price stabilize the rotation, Tulowitzki play incredible shortstop and hit a bunch of homers, Revere stabilize the outfield D, and the guys in the pen help add depth so they could finish off games. Most of the games they were losing in the first half were close games the bullpen would blow or poor D would cost them. Fixing those leaky areas led to a lot better luck.

Now in the Padres case I see the writer has a point they lost a lot of good players (they did pick up Cease and Arraez) and yet have performed better. I do think some of that has to do with a reversal of fortune but I also think their division is a lot weaker this year and generally there are a lot of mediocre teams across MLB this year.

In looking at their schedule I have noticed they are a very streaky team. Recently they lost 5 in a row and then won 9 of the next 10. Earlier in the season they lost 6 in a row but won the next 7 out of 9. So maybe they are experiencing the extreme forces of luck levelling out for them this year.