The nail clipper hole stayed because it never created problems in design.
It is cheap, useful in multiple ways, and easy to manufacture.

That combination made it a perfect “forever feature” in industrial design.
Even as technology improved, there was no reason to remove it.

The hole also reflects a bigger idea in engineering: simple tools must adapt to humans.
Not every user has the same strength, grip, or comfort level.

Because of that, even tiny details can improve usability in subtle ways.
Designers value features that work quietly without needing attention or explanation.

Over time, people stopped noticing the hole at all.
And that invisibility is actually proof that the design works perfectly.

Today, it remains unchanged because it still does everything it needs to do.
A tiny detail that quietly survived more than a century of innovation.