Honestly?
Imagine you buy BfA after not playing Legion, getting hyped about the new races just to discover you have to run around on empty Argus to grind a rep nobody gives a damn about anymore, killing old mobs with one hit, looting loot or currency that is completly useless to you.
And I know, there are tons of people who HATED WoD and skiped it (I actually enjoyed and played a lot of it), and they would go nuclear, if they had to play just a bit of old useless WoD content 2 expansions after it ended.