more specifically, they all have the same inside width. The side plates are narrower but the pins and rollers are the same width

Leonard Zinn disagrees with you.

"Yes, chains have gotten narrower as the number of rear cogs has increased in bicycle drivetrains, BUT it is only the outside width dimension that has decreased, and really, we are actually describing the length of the roller pins, which is shorter on 11-speed chains than on 10-speed chains."

Since the pins run the full width of the chain, they would naturally be shorter on a narrower chain .... but the rollers are the same width on 6-11 speed chains, is what is claimed accurately (unless that is inaccurate.) :D

oh right, the pins obviously would be shorter by the width of the plates, but the wear portion of the pins, which is the width of the rollers, is the same between 10/11 speed, 2.3mm, which is why the cogs are still the same width.
https://gzmyu4ma9b-flywheel.netdna-s...n-photos05.jpg
10L/11R