When Mearls said that 5e would be designed so that fans of each previous edition would have some of the things from their favorite editions included, that does not mean that Mearls promised to make 5e appeal to every single fan of every single edition.
It was never a realistic goal. And it was never limited to just 'some of the things,' it was ideas like, you'd be able to make a character like that of your favorite edition,
and play it along side others' who liked different editions.
Really, very out there.
Holding them too it may seem a bit unfair, but,
it was also the very justification for having 5e at all. That more recent editions had failed to include or support playstyles of fans of earlier editions, and WotC needed to do just that, with 5e, to 'heal the rift' in the fanbase.
And since 5e has players and fans who were fans of every other edition before 5e, that means the goal was met.
Different fans liked different things about past editions. Psionics
has fans who specifically like what it did for the game in one or more past editions (it was in
all past editions, afterall!).
Besides, D&D has fans who had been fans of
every past edition, and will be fans of every edition to come, because we're just that loyal.
Having many 1e-4e fans like 5e, but not you, doesn't mean they failed in that statement, or lied, because you don't represent all the fans of any particular edition.
Cutting psionics doesn't lose
me. For most of the last 39 years, I've rather loathed psionics, considering them a sci-fi bit with no business in D&D. It was only c2010 that I relented.
But just because
I'm getting some stuff
I wanted out of 5e (like a Druid that ticks all the boxes to feel like a Druid for the first time since 1e), doesn't mean I give it a free pass on coming through for other fans, as well.
There is no way 5e can have every element of every edition.
It's a finite list of elements. The structure of 5e, if not quite as fully modular as suggested in the playtest, is open to optional rules. It absolutely can do exactly that. And, people who don't like a given optional element, need never opt into it.