He could, but he's under Hashirama.
That's basically like me asking you how the Sage of the Six Paths counters kotoamatsukami, and then as you have no manga fact to prove me wrong, I could go say Danzo > Sage of the Six Paths.
we haven't seen rikudo's power so don't speak about someone didn't appear yet
you logic can't be used with character who his power was appeared
that is fact hashiram can't counter kamui
and obito's chance to beat him >hashirm's chance to beat obito
by your logic i can say anyone is stronger than another anyone
we compare powers not nicknames