Just to weigh in on the Lucky/IPK set, I think that it shows very little about Fox's dominance in the metagame. It's just that the Lucario/Fox matchup is very tough. IPK has been playing a lot of sets across tourneys against Westballz, K9, as well as some Wolf players down in Socal, but Lucky has not been playing very much PM and only really played against IPK's Lucario that day. Lucky is a highly adaptive player and navigates the neutral game phenomenally. And the thing about Lucario is that his neutral game is highly exploitable by a character with the mobility that Fox has. If you watch the set, IPK gets fairly clean punishes on Lucky, but a lot of them were from missed techs and punishes rarely went past ~40%. Fox, on the other hand, can waveshine across the stage into an usmash and snipe out an uair, netting lots of %. Lucky can "just do Fox things" because many characters with high mobility can just play their own game against Lucario. Most of Lucario's strengths lie in his punish game and his mixup potential with aura. Lucky simply outspaced or outmaneuvered all of Lucario's options (You see a lot of whiffed down-b utilts in the set). Because Fox is a high mobility character. So is Falcon. So is ZSS. So is Sonic. All of whom I believe can give Lucario problems. And all of whom will show Lucario struggling in the neutral just like Lucky has with his Fox.
I just think the set highlights how tough the matchup is if anything. Lucario gets small punishes, gets comboed very easily, has very weak OoS options, and can get edge guarded by Fox bair pretty cleanly.
Fox gets edge guarded if Lucario burns an aura on the super-ball. And he gets comboed hard if he doesn't tech.
Both players are of top caliber, but matchups are matchups and Lucario loses this one. A drop in the bucket as to why Fox may be OP, sure, but definitely not a central reason for it.