I reckon Gottlieb must have had a good reason to design it like that. Maybe it gave a better feel, maybe it allowed for a range of adjustment and the springiness of the wire evened it out, maybe it allowed for shorter cable runs to the coils, making the flippers a bit more energetic. I really have no idea why it was designed like that but I'm sure there was a good reason. It certainly wasn't cost, it would have been mach less expensive, and much simpler, to put the switches on the cabinet sides, right by the buttons. As they made the games less expensive to manufacture, that is exactly what they did.