Even if this did happen it shouldn't necessarily disregard High Elves from happening, but this is besides the point.
Main thing I want to point out here is that if it does indeed keep being held out of reach (Blue Eyes for Blood Elves) then there must be some reasoning for why Blizzard is doing it so. My guess? The simplest one: Blue eyes are being used to signify High Elves, therefore this will be kept unique to differentiate that group. Whether they become playable or not is of no consequence, since currently that's being used to show the difference between the two physically.
Just as very soon we'll have Night Elves who will be "Night Warriors" defined only by Dark Blue Eyes, with a slightly off-color skin. That's enough to distinguish them from regular Night Elves.
I'll go on to extrapolate that we also will never see Wildhammer Dwarf tattoos added to current playable Dwarves, because that is their unique signature in how Blizzard portrays "this is a Wildhammer" vs "this is a Bronzebeard".
I think that while Blizzard does make a lot of gameplay concessions, they are also very conservative about upholding their aesthetics and differentiations (hence Ion claiming high elves not 'unique' enough to warrant an AR atm, similar answer was given about WH dwarves).
So the argument that "it's never going to be added therefore it shouldn't stay unique to NPCs" is a flawed one, since Blizzard can intentionally be doing it to keep things flavorful/unique.
Blood Elves with Green Eyes is just way too iconic at this point, even if in this discussion many BE players are piping up now to say Blue Eyes should also be available because "we're the real high elves per Ion" it's not something iconic to Blood Elves and hasn't been since their release in World of Warcraft. Ion can keep being brought up, but what a developer says vs what is actually added to the game is a whole other ballpark.
This is another issue I've been seeing a lot with the anti-HE peeps. "feel like a real High Elf" when the game, and now heritage armor scenario goes out of its way to showcase what it means to be a Blood Elf. This is what makes me believe why there is so much toxicity from Blood Elf players who are involved in this conversation. Because the truth is that most want to "feel like a real High Elf" when in fact they should be trying to own the Blood Elf concept. But these players come off as not wanting to, and that's where I see a lot of the opposition for getting High Elves added to Alliance coming from.
Nevermind that Blood Elves focus much more on the Light now rather than Arcane, that they're much more pragmatic than idealistic, that they kept themselves xenophobic. Nope, they want to "feel like real High Elves" by dismissing what makes their character a Blood Elf and rally for their past society.
The heritage armor scenario shows this for Blood Elves as that is what it's meant to do, but already I keep seeing so many Blood Elf players brushing it off as if didn't add anything new.
This is like if Night Elf players made their characters out to be Highborne when that is a relic of their past and they don't have the claim to it anymore. Hence why Nightborne are filling out that niche.