When I started playing Pathfinder, the only rulebooks were the Core Rulebook and a bestiary.
The game provided a simplified and sane collection of "best of the game" D&D 3.5E rules for folks who wanted to keep playing that.
Players did not have as many options, but they were more-or-less balanced and sensible options all collected in one place for easy reference.
Since then, Pathfinder has jumped the shark. It now has so many rulebooks that there is no point to owning them. A player or GM needs to search through all the books to see all of the options for a situation. This is best done online.
The same "too many books, too many broken combinations of options" problem that Pathfinder was created to fix has returned.
(The latest example is an eleventh level Half-Elven Oracle with Eldritch Heritage in the Arcane Bloodline who uses Paragon Surge to temporarily get Improved Eldritch Heritage or Expanded Arcana. This character has nearly instant access to every Wizard and Cleric spell up to fifth spell level.)
The setting of Golarion also moves farther and farther from my kind of fantasy setting. The world has increasingly dysfunctional economics because of how much wealth PCs are expected to gain.
As someone who grew up playing AD&D, even the idea of a "magic item shop" seems silly. A lot of the fun of AD&D was finding creative ways to use the wacky assortment of strange items you found in dungeons.
In Pathfinder, adventurers instead sell (for half price) the items they will not be using daily and with that money the party Wizard crafts (for half price) more practical but boring magical equipment.
Now Pathfinder has an entire book devoted to magic item shops!
Perhaps I am too critical. Maybe the book actually makes magic item shops someplace where Golarion's adventurers buy stuff, instead of only selling items there to get the gold the party Wizard needs for his crafting.