Pathfinder is a game for people who like to build characters. If you don't really care about that aspect of the game, there are other systems that will suit you more.
What I love about Pathfinder is that there ARE so many options and sources available for both players and GMs. I enjoy having dozens of races, classes, and archetypes to pick from. The possibilities are endless, and characters are extremely customizable. I have never understood people who see a game with dozens of source books, setting gazetteers, adventure modules, and six different bestiaries and thinks it's a bad thing. What others call 'bloat' I call 'variety'. Also, if you do have a problem with so many options, you don't have to buy every single book that comes out. Most of the information in those dozens of books people complain about having to buy is available free online through the various SRDs. I've made three different Occultist characters and still don't own a copy of Occult Adventures. In fact, one of the major things that has kept me from getting into D&D 5E (apart from disliking advantage, overpowered characters, and neutered monsters) is that there are only really four books with player options, and they seem reluctant to produce more than one bestiary. I also enjoy that Pathfinder has more than just a handful of skills as opposed to just a handful like in 5E or none at all in the case of many OSR games. More skills means more customization. And while it isn't required to set your games there, I very much prefer the world of Golarion to Faerun, Krynn, or even Eberron.
So some background info: I've been running games for five years or so, off and on. I've played/run Savage Worlds, Apocalypse World, Fate, d100 games, OSR games, and 5e. In no particular order.
Now, you'll notice two big omissions there that seem to define the internet discourse surrounding Pathfinder: Pathfinder itself, and the game people came to Pathfinder in protest of, 4th Edition.
I see another "big" omission that I think will also skew your perception and that is 3.0 D&D.
I've been playing d&d since 2nd edition and I was in the middle of a long running campaign when 3.0 came out. Some of my players were really interested in trying it out but I was hesitant at first because 3.0 seemed really different from 2nd. But eventually we gave it a shot, converting our 2nd edition characters into 3.0.
The big thing that we all noticed right away was that 3.0 allowed a lot more freedom in terms of multi-classing and equipment choices.
"you mean fighters get to be proficient with ALL martial weapons?!"
mindblown
It also introduced the "d20 system" which was an attempt to condense the complicated rules of 2nd edition and streamline them. Everything was now determined rolling a 20 sided die instead of rolling percentile for this, a d12 for that and a d20 for this other thing. The reduction in complication made it easier to wrap your head around how "good" a particular ability was.
This expansion of options and ease of customization is what most players tend to notice.
3.5 was an attempt to fix the flaws of 3.0 and pathfinder was an attempt to fix the flaws of 3.5. 4th edition boosted the popularity of pathfinder by disenfranchising players who loved 3.5 and refused to go over to some "third party" who had "stolen" D&D.
People didn't move to pathfinder because it was better than 4th edition, people moved to pathfinder because it was the newest system that still "felt" like D&D. I've played 4th and it was fine, but it didn't feel like d&d. It felt like a fantasy themed superhero game.
So, while it's true that pretty much any well made RPG will allow "lots of customization" I think what players mean is that pathfinder makes it "easy" to customize a character because the d20 system makes it easy to understand how a particular ability works.
I've spent hours making a character in gurps, was the one and only time I had a character literally die during character creation. But that was largely because I didn't understand the system fully.
Does any of this make pathfinder "more fun" than the other systems you've listed? If you have a good GM probably not. But people like to play what they know.
I don't know if this is a satisfactory answer or not, but in the end I think people like pathfinder because it has a relatively easy learning curve while still providing lots of "meat" that's easy to dig into once you learn the system.
Edit: I just realized, I should really pay attention to timestamps. The OP created this thread on April 2nd and their last reply was on April 2nd. It seems unlikely at this point that they will or have seen anything since then.