Memes

It is. Taller = More for many people. When we are children, we actually think tall and thin = more than short and wide. We lack the logical skill to figure out that 2 glasses of such shapes hold equal volumes of water.

Even though this skill develops later in life, many people are still subconsciously wired to think tall = more. Therefore tall = better.

There's other things at play here, like stacking more cans per shelf, which makes it look like it's squeezing the competition => better.