The key to the P-51 was not its "laminar flow" wing, but in the attention to detail and manufacturing "cleanliness". NA was able to manufacture an airplane with better skin waviness and smaller panel to panel mismatches and gaps. Curtiss and Bell aircraft often look like someone put them together with a big hammer.
Part of that was tooling. I know one company that was still tooling the forward fuselage to an inner mold surface into the 21st century. Added stringers, frames, clips and then external skin, and all the additive tolerances. No one should be surprised how ragged that ended up looking.