Well, if you're to believe the company, it sounds like the 747s brawniness isn't as required as it once was in the pacific.

Supposedly if Delta owns a retired aircraft then they like to part it out, and 4 parked 747s would be a lot of parts to save money on. I think it's odd to do this after the interiors were done but you can part those out, no? So it'd make sense you'd improve your margins on some routes and reduce the cost of operating the 747s on the routes they still reign supreme.

So couldn't it just be that mathematically fewer 747s equals more profitability?

I argue we're a 767 airline. I think that's the nature of operating a global airline from the States where the 767 or now the A330/350/787 would make more money most of the time than a 748, 773 or 380.