I've thought this before but if it was that easy it would be done, obito noted the ten tails skin is really powerful, plus I'm sure when it reaches its next form it will get the 9 tomoe sharingan, then the rinnegan in its final form, and then it will have all powers of the 6 paths and all natures on top of its powerful chakra and defense. that would really make it invincible and the "progenitor" of all life. I'm sure sasuke is going to shoot yasaka magatama at the 10 tails and the 10 tails will either take it, or just brush it away before it reaches him. hell I'm sure the juubi knows how to do amaterasu