I agree with this, but with an added caveat. Luffy receives aid from others because of his philosophy on being King. Like regular non-Luffy pirates, Kid seems to be set on hoarding the glory and fame that goes with being Pirate King, which gets him shunned. He'd probably refuse aid either way, but it's never really offered. I had similar thoughts on the difference between Luffy and the other WG member after Robin's "Luffy doesn't care about the WIll of D" last week.
I think Luffy might never become individually stronger than emperors or admirals, but he'll always receive help that'll make him king. As he's not actually trying to become a traditional king. In One Piece's world, that's the most terrifying power like Mihawk said.
It's an interesting way to incorporate "plot armor" in your narrative, but unfortunately Luffy doesn't get appreciated among some hardcores because of it.