Based on what evidence?

Random sampling of my guitars: 12s (light guage) on two, 13s (medium guage) on one, 14s (heavy guage) on another though it's tuned down, 9s on the electrics, blah, blah, blah...

How then do we explain the 12 string with 10s, but doubled? Or the mandolin likewise? The bass?

Factor in scale lengths, hand strength and size, setup standards, string alloys, pitch, orientation of the planets, not to mention the illinformed nature of guitar council provided for free by mentally challenged store employees, and you end up with...hog wash. Is hog wash one word, two words, or hyphenated?

You think you've got problems? Try to find left-handed guitar strings these days...

Peace, Mooh.