I find the basis of your premise rather faulty, as both Darnassus and Undercity are still accessible in game. In fact all of my Alliance alts (and my Blood Elf Death Knight I use to roleplay as a High Elf that I haven’t logged on to since before the War of the Thorns event) are parked in Darnassus right now. Blizzard went out if its way to leave these capitals available for gameplay purposes, despite your accusations that no on was using them (for gameplay purposes).
However, while I would not use the same tone as you do, I think you’re not entirely wrong on this if Night Elf fans do feel down, because as Kyalin points out, when you actually look at the lore:
So I am proud to be one of the people around that fits this description when it comes to negative claims on the state of Night Elves around here: