Obito went in so much trouble to convince Sasuke to join him, help him.
Obito saved Sasuke from the Kages.
Told truth about Itachi.
Obito gave Itachi's eyes gaining Sasuke the EMS.
Also maybe Sasuke might Not retreive & just kill the 9tails if he can.
But, nowhere does Sasuke shows royalty, respect towards Obito for that. He didn't join Akatsuki. As soon as Sasuke gets what he need he's on his way. So my question is ultimately Obito went trough all this trouble for nothing?