As a Uchiha unlocks stronger versions of the Sharingan his chakra becomes stronger and more abundant (Karin noted how cold Sasuke's chakra was and Madara was able to push Hashirama to the limit).
Also, where do you think Susanoo comes from and is sustained? Why do you think EMS users stop straining while using MS jutsus?
I only remember someone who was out of chakra when facing the Mizukage. He is using a technique that requires a lot more chakra, it will be spent more quickly. Also, Sasuke has extra chakra from CM before.
The Gokage are not weak, still got destroyed by Madara.
Are you really comparing two kids to a MS user capable of defeating most kages in existence?
MS Sasuke can beat a rare few kages in existance maybe, loses to most of them. It seems that you're not getting the point. Sasuke got a lot more powerful from the curse mark as seen in VoTE, you think that doesn't apply when he's older?
How is that a factor? Why would Sasuke strain himself when he has the exact same weapons as his opponent, minus some inferior ones compared to MS Sasuke's superior alternatives.
The fact that you don't think it's a factor just proves how broken this vs section is. How is strategy a factor? How is intelligence a factor? Mental state is everything in a fight
Any manga material to back this up?
I just told you
There's so many wrong, personal claims in this last part that i'll just ask this: Do you really think Sasuke gained an upgrade only to become weaker? Because that doesn't even makes sense plot wise.
Where did I state that he was weaker? He is more powerful, just not as smart or careful as he was before. At least not while fighting the kage.
You don't have to convince me that crazy MS Sasuke is stronger than Hebi Sasuke. It's a good match up when you think the factors involved, mental state being the most important one.