He didn't say High Elves are possible. He said anything is possible in future, and he said 'we have no plans for that in BFA' to that person from the High Elf discord whose day he was trying not to ruin.
'No plans for it in BFA' does not mean it becomes possible once BFA is done, in the same way a politician who says no tax rises in this term means there will be tax rises in the term after. It means no plans for it in BFA. And it looks like no plans for it in Shadowlands either.
'Anything is possible' is a verbal tic he throws in after he has ruled out something out to cover himself. That is it. It's lawyer talk. He said it to pro High Elfers on High Elves, he said it to Preach on Master loot, and Preach isn't going around saying 'master looting is coming back eventually, Ion said is anything is possible.' And it is not his fault that you read way too much into what he said when his meaning was blatantly clear. No plans now, no plans in future and if it ever happens it will be due to a set of circumstances he couldn't foresee.
After all, the rationale he gave for rejecting Alliance High Elves is evergreen. It doesn't have a time limit. Faction identity and faction diversity didn't suddenly start mattering less because BFA ended. Those are eternal concepts in wow. They spent the last Blizzcon repeatedly rubbishing suggestions that the factions were going away or being weakened. As long as factions matter, playable high elves for the alliance wont happen.
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The problem with your response, with it's litany of references to all these other races is that somehow you keep missing the fundamental point. Are wildhammer Dwarves playable as a Horde race? Are Desert Trolls playable as an Alliance race? Are they even available at all?
No, no and no.
High Elves are not an unavailable option. As Blood Elves, they are currently playable as a core race of the Horde. And you are arguing that that core Horde race should be duplicated to the Alliance somehow. If not by a dedicated alliance race slot, then through pretending with a Void Elf.
None of the other examples you bring up matter because none of the other examples have the unique issues the Alliance High Elf request has, and your refusal to engage with this renders your retorts pretty hollow.