I'm not sure about that. Are we counting in feats? If so, and assuming the SA limit to one per turn stays the same, then Extra Attack doubles the chance of SA applying (which can be managed in other ways, e.g. on your reaction). Kind of like having advantage. And adds in a fraction of your weapon + modifier damage dice. The power-attack feats are stronger.Well, you are wrong, in terms of math. You are welcome to your preferences, but math is objective. WotC will never design an Exta Attack Rogue, because it is out of whack with the math of the game.
I think of those feats as the envelope: the edge for sustainable one-target damage is Reckless GWM or equivalent. I'm pretty sure Rogue is within that, even with Extra Attack.