Popularity means nothing.
It's all about match-ups.
That is what the list is based on.
Also you overrate Aura sphere, but other then that Lucario is pretty solid.
And I don't think he does well vs alot of the top tiers. I think he has disadvantage to alot of them or breaks even.
You don't talk about his weaknesses much. Like his low mobility and how he is forced to approach vs people that camp him but thanks to his low speed and mobility this makes him more predictable and easier to zone. His smashes are very safe, but they are slow to come out and U-smash ain't that hot. His tilts are not as safe. If they are blocked then he is punishable. He is also pretty easy to gimp. By far one of the easiest to gimp. Yeah he can wall cling, but that matters little since your opponent can just ledge drop to fair or w/e and stage spike him since Extreme Speed has no hitbox. If he goes on stage you can just wreck him and get him back off the stage or kill him.
Also let's get this straight and it's not even debatable. Lucario is not a good camper. Falco is a good camper. Toon Link is a good camper. Pit is a good camper. Lucario can't compare to them in this department. He is a good comboer until his oppenents get to higher percents. Then he can't do much in terms of damage unless he has some damage himself.
You also overestimate his range. Only F-smash, U-smash, and Force Palm have insane range. The rest have good range.
You compare Lucario to Marth alot.
You should stop that. They are completely different beast.
I'd like to think it's about match ups, but unfortunately, if a character isn't popular, they're not going to be played in tourneys very much, and there will be less people who win with them, which seems to effect the tier list. It did in Melee.
But Lucario has plenty of mobility and his speed is in his attacks. He's not a slow character at all, and his tilts are extremely safe. You can't very well shield grab his Ftilt because it hits twice and pushes you back way too far. Even if you powershield it, the second hit will just knock you into a normal shield. If you dodge around his ftilt, he'll still have enough time to put up his own shield or even Double team if he's feeling lucky.
Lucario isn't easy to zone at all for the simple fact that he does have more range and priority than a majority of the cast.
You're underestimating his range. His Ftilt has the same range as Marth's ftilt, which is generally considered a move with large range for an ftilt. His Dtilt has about the same range, only low enough to shield stab, and his Utilt doesn't have the same amount of range, but is incredibly fast and has hardly any lag to it.
His Fair has a sweet spot that reaches waaay past his foot. The range on that move is seriously massive, as is his Dair, which is also deceptively long-ranged.
Yes, gimpability is one of his weaknesses, but Lucario is a floaty character who doesn't need to recovery horizontally very often, especially with good DI, and from a ledge cling, he can always air dodge on the way up, too, although it's difficult to time it on stages like final destination. Either way, his air jump is quite large and goes a good distance which aids in recovery. Other than that, his only other weakness is the lack of power at 0%, which is something that doesn't seem to pose as much of a problem for good Lucario players as it does for beginners, especially since he can chain throw most characters to at least 60% using nothing other than force palm and a running grab.
Lucario's approach is much better than you give it credit for. Good Lucario players don't need to use his smash attacks unless absolutely necessary. And you'd be surprised at just how useful his Fsmash is when it's done from a stutter step or pivot, given the lingering hitbox, it can sometimes even trap someone who's trying to roll behind him. And Lucario can throw out a string of Fairs from a short hop, followed by a Nair which has next to no landing lag, which makes a fine approach. His Ftilt alone is good for approaching, as is his dodge, which I'm sure is abundant in I-frames.
And he is a good camper. Not quite as good as Falco or Toon Link, but better than most of the cast. He can also approach campers quite nicely given his wealth of defensive options, and the ability to weedle his way through projectiles at close range with a well-timed double team.
And I compare Lucario to Marth because they have quite a bit in common concerning hitboxes, priority and aerial ability. Out of everyone else in the game, Marth is the one whom Lucario shares the most similarities with. He has a Ken combo, a counter move, similar range on most of his attacks, a similar out of shield game, less-than excellent recovery and similar approaches (Fair, Nair, etc.) as well as an rangy Fsmash with a tipper and a sweet spot.