It seems like guitars that focus on more of a 'traditional' body shape don't have the arm contour. By that, to me, it seems guitars influenced by the design of the Gibson Les Paul and its derivatives. And all of those just really seem like they are based off of the design principles of the steel string acoustic, right?
Leo Fender threw all of that out the window, basically. He changed the game. And kind of ushered in the era of playability and ergonomics into the guitar world. I'm with you. I enjoy all guitars, and can play whatever, but my heart is always with Strat-type guitars, and I love the comfortability provided by that arm contour.