Limited criteria in those rankings and focused on occasional travelers. Even with those, I'd think that Miles' expiration, airports covered, and mainline vs RJ fleet might help Delta a bit. For a lot of us the Elite program, quality of F, upgrades etc matter much, and those criteria were not included.

Sure. Southwest and Alaska are great airlines to fly for occasional travelers who fly from their points A to B. Good luck flying them to Europe from the East Coast.