Airline ticket prices go up and down like a French whore from Marseille. And airlines tickets, like whores set their prices based on the clientele they wish to attract and their demand. So while $4500 may not seem like an affordable price to some, to others that is the price one pays for a few hours laying flat under the covers while being served.
PS: Welcome to FT, and be aware your duplicate thread/post will be deleted as multiple posts are against the TOS. And this thread will likely be moved to the Delta forum as it is more Delta specific.