He gave the answer he had to give based on their current plans.
I like how no Anti-helfers aren't commenting on the fact that John Hight in a recent interview already said they have them all planned out. Can certain notices make them change their plans? Certainly, but has he said, they definitely have a plan.
When you take these reasons it's very clear to see that the races we know of right now were already planned from the get go.
1) They wanted Legion races given before BfA. So this makes HM, NB, and LF self explanatory.
2) Alleria was hinted at in WoD to be related to the Void or at least where one of her arrows were found. Thus that was clue meant to show her story leading to what happened on Argus.
Her Void Elves were given as a prop to her story, now she can be more involved. Vereesa is the leader of Silver Covenant and instead of making Alleria the leader for High Elves they just gave Alleria her own set of elves so she can be a leader herself.
Y'all have to face it that regardless of High Elves, Void Elves were made to give Alleria more story than anything else. Of course we will probably see some development of Void Elf story because they're the one lacking much at all compared to the other 3 legion races.
3) Now we look forward to the BFA races. Obviously Zandalari and KT are self explanatory, expansion centered around their landmasses.
So what about Dark Iron and Mag'har? Here they've mentioned that Dark Iron were the ones that based on player feedback they decided to implement. This because they've been asked for many years (hmm sounds familiar to High Elves don't it?).
Because really take a moment to think, what would they pair Mag'har with? High Elves? They already released a set of elves, they're not going to release another set so soon.
4) That interview also says that the way they decide on AR is to see which faction is having too much of one thing (cute races vs tough ones) and then they decide to give that theme to the other faction to balance it out.
Like they say from that interview, "Horde can't just be all ugly races right?" This made me OMEGALUL .
So based on the above info, it's pretty clear to see why High Elves wouldn't come out right away. I mean someone could say the same thing about Ogres, they've been highly requested for so many races and why didn't they come out with Ogres immediately?
It's always going to be incredibly stupid to take the position of "if it's not in now, it never will be" that some people are taking, since Blizzard has a pretty open track record of eventually implementing things that have historically been highly requested. Even if it takes them "forever" to get around to it and even if previously they've explicitly said "no" on the matter (spoiler: Ion didn't say No High Elves forever).
But yes, all Anti-helfers, keep taking the position that since something isn't in now, it'll never happen. We already see some saying if High Elves do happen then they'd most likely play one (of course most would that's why they're clearly popular).
Like that Ron Jeremy poster said, they can always develop High Elves to make them different enough to be added if they currently don't feel up to snuff. It's very clear that their plan with Allied Races right now is going to be to come out with the biggest visually different races.
Again this is supported by Dark Iron over Wildhammer, Void Elves over High Elves, Kultiran getting extremely new looks, etc. Heck even John Hight said that Mag'har complete clans idea was because you can't tell much difference between the Orcs when they're armored up (hm same arguments people brought up with regards to Void Elves vs Blood Elves) hence why they decided to include all the clans in one go. So they're not stupid, they want the races coming out right now to be visibly different enough through armor. So yeah High Elves as they are currently would fail this test.
But let's see what happens the next time elves get added to the Alliance. And oh yes we will see more elves, not for a while but someone would have to be pants on head dumb to think no more elves will get added.