So, we know that in order to get EMS you have to take the eyes of your brother - who has MS - and put them in place of your MS eyes.
Now, the way EMS was obtained always resulted in 1 of the 2 bro's dying. Izuna was sick and Itachi was already dead.
What IF Sasuke and Itachi were both alive, both had MS and they simply traded eyes? as in Itachi took Sasuke and Sasuke took Itachi's. Kind of like card trading
Would both get EMS?
Also why did Tobi give Sasuke Itachi's eyes when he could take one of them for himself and gain Amaterasu or Tsukuyomi?