What confuses me about the Skyborne... Why?

Yes, I get it, elves are popular and sell well.. I prefer ogres and similar but FINE... elves are elves, I can deal.

But... Why go for Skyborne / Sky-elves? Maybe it is just me, but that seems so completely unecessary. Highelves / bloodelves are right there!

Re-use assets from TBC, open up quel'thalas, have the area be split between the silvercovenant / high elves and the blood elves.

That has to be cheaper, faster and easier than inventing a whole new subrace from scratch. Especially as people have been begging for high-elves for literal years.

I am genuinely so confused over this.