Absolutely. Wasn’t trying to disagree, just thought I’d share my weird experience where it did matter.

Exactly. That’s why they put a “heavy” sticker on the bag even if they don’t charge extra.

I think you’re right, in general, about the effect of one person’s weight, but I was on a weirdly empty cross Atlantic flight and they reassigned everyone’s seats and told us we couldn’t move until after takeoff because they needed the plane to be balanced.