I'm gonna put in a vote for simple happenstance. The number of people who look at or search nickels is nearly insignificant compared to mintage so you'd never notice a trend of people who roll without looking vs people who do. Even War Nickels, which have been circulating for almost 70 years, are virtually unknown to most non-collectors.
People just don't look at coins, they are recognized by size and color.
People just don't look at coins, they are recognized by size and color.























