Well. Notice how he didnt have the traditional Ashura cycle
Ashura was weaker than Indra (indra had a headstart by being a genius)
Hashirama was better than Madara throughout their entire lives.
Then Ashura picked a non direct descendant(speculated that Uzumakis are from Hamuras line and not a branch of Senju)
Madara was still no match against him even with full stabilized Susanoo and full Kurama.
The question you should be asking is "when will Kishi explain it?"