Why Legenday and Warner Bros. should have Mecha-King Ghidorah in godzilla vs Kong

Ah,Legenday,Legendary copied Legenday.

Mecha ghidorah would be a very popular opponent.

So would Mechagodzilla, however. 

Um... why? The topic says "why" in the title, but it's not stated here. That being said, I'd like him in either this movie or the next Godzilla movie, since Mechagodzilla is also an option.

i think because Alan Jonah buys Ghidorah's head