Or simply the official pathfinder devs don't care about psionics, which is a sentiment I can symphatize with. Starfinder for example doesn't have any either.
I'm pretty sure of my interpretation, especially since there is a large group of people who will pay good money for psionics books and Paizo is a business if nothing else..
I would even disagree with the "large" bit. Just look at how much psionic homebrew there is when compared to, say, Tome of Battle, that got exactly one book in all of 3rd edition and zero support in splats. There are psionic psionic fans I won't deny it, but they're a pretty small segment all in all. That Paizo does not bother doing it themselves is just bigger proof of how little of a crowd there actually is.
Basically there's a reason that Paizo could go out there and make an RPG that actually outsold official D&D itself while dreamscarred press remains some 3rd party company latching into the next big thing.
Also Starfinder only has one kind of magic so I assume psionics just gets rolled into that and I expect the system to never have psionics (also psionics are never part of the core books in any system I've read besides weird stuff with randomly rolled powers).
Technically psionics are in the 3.5 srd. Paizo could've just copy-pasta'd that and psionic fans would've bought it. But again, simply too few of them to be worth it Paizo's time even for a simple carbon copy, while D&D 4e attempted to do psionics only to go down burning and crashing.
And Starfinder is sci-fi so they could've called the mystic powers psionics. But Paizo just doesn't care.