Originally Posted by JAIF

If Madara was losing in a fight against Shodai... he would summon the Kyuubi. [Assumption.] The Kyuubi was so powerful Yondaime had to sacrifice his soul to seal it away. Yondaime was stated to be superior to Shodai. [Proof?] Therefore, it is a logical impossibility that Shodai could defeat Madara under normal circumstances.

To further that notion... Madara was stated to have been the greatest Uchiha, which means stronger than Itachi. Itachi was stated to be beyond Orochimaru's reach no matter the circumstances. Orochimaru with Edo Tensei defeated old Sandaime. Old Sandaime could hold his own against the ressurected bodies of Shodai and Nidai Hokage at the same time, which could also regenerate and didn't tire out. [The ressurected were also mindless and made no attempts to dodge.] No matter what kind of non-linear approach you assume, this kind of gap is ridiculous. It's like saying that Konohamaru could kill someone like semi-Kyuubi Naruto under the right circumstances.

Also, chakra potential doesn't equal power. Chakra doesn't equal power. Chakra potential doesn't equal chakra. Potential doesn't equal power. Similar lives don't equal similar attributes. This theory is flawed by definition.