For the D&D community, psionics is like 4 very different and distinct things.
So WOTC offshore the more complex ideas to 3PPs.
The problem isn't that it means different things to different people.
It's that WotC's chosen design method for 5e is design-by-committee, just via survey. When there's a clear agreement about what something should be in broad strokes, e.g. everyone agrees Druids should have shapeshift (but might quibble about fine details), then this method works.* When there is deep
disagreement, on the other hand, it is completely nonfunctional. That's why they tried like four shots at fixing/changing the Ranger (and Sorcerer...and Monk...and Warlock...), why they tried like three or four times to create a Psion, etc., etc.
Simply put, outside of a relatively small set of basic things--
very loosely the "core four" classes + Barbarian, Druid, Paladin, and
maybe Bard--it is WILDLY impractical to demand that 70% of the community agree on a design before you begin iterating. Frankly, it's impractical to demand even 50% approval before proceeding, because no group has a clear majority opinion. At best, you'll see a plurality of about 40%
if you're lucky when it comes to psionics, because that more than most things has extremely strong opinions and a lot of them are....let's say "at loggerheads".
Up to a certain point, particularly with the most "general" classes, it's very good to ensure you have a broad base of solid approval before you proceed with your designs. Fighter, Cleric, Rogue, and Wizard are all intentionally pretty generic classes. They aren't "for everyone" because nothing truly is "for everyone", but they're about as close as you'll get to "for everyone", and thus having the thumbs-up, even preliminarily, from a clear majority of your user base is a good idea. (I'd personally make it "anything clearly over 60% is fine, but if it's between 60% and 70%, try to figure out what the folks who aren't on board don't like, and address it", but that's just me.) After that point, however, trying to make sure that EVERY class ALWAYS gets an unequivocal supermajority is not only a waste of time, it's actively harmful to the game's design. It leads to milquetoast slop like what the 5.0 Sorcerer and Warlock were--barely functional compared to their peers and actively conflicting with the way people really play the game--or things being stuck in eternal development hell, as happened with psionics.
And now we're stuck with the worst of all worlds: psionics that are very literally just
more spells that work exactly like all other spells.