Bich made the ballpoint cheap enough to throw away

After World War II, Marcel Bich ran a French workshop making parts for fountain pens when he encountered László Bíró's ballpoint pen design, licensed from Argentina, which used a rolling ball tip to avoid the fountain pen's ink reservoir and nib. Early ballpoints on the market were unreliable — the ball's fit against its socket was imprecise enough to leak ink or skip and clog — so manufacturers priced them as premium alternatives to fountain pens rather than replacements for them.

Rather than add more engineering to make ballpoints reliable enough to justify a premium price, Bich pushed in the other direction: use precision Swiss watchmaking machinery to manufacture a steel ball sphere accurate to one hundredth of a millimeter, then strip everything else about the pen — the barrel, the cap, the mechanism — down to the minimum needed to hold that ball and its ink, made from injection-molded plastic instead of metal or fine materials.

Spent precision only on the ball's fit in its socket, the single failure point, then made the rest cheap and disposable — a plastic barrel and cap for a replaceable tool.

Precision on the ball eliminated leaks and clogs, the core reliability issue.

Cheap plastic barrel and simple design made the pen affordable as disposable.

Disposability changed consumer mindset from maintaining to replacing pens.

High volume manufacturing made the low price sustainable and profitable.

When a cheaper alternative fails on reliability, don't add engineering to match premium quality; invest precision in the one failing component, then strip the rest to the cheapest form that works.

Over 100 billion Bic Cristal pens have been sold since 1950, making it one of the best-selling manufactured products in history. The Cristal shifted the world's default writing instrument from the fountain pen to the disposable ballpoint within about two decades, and its hexagonal transparent design has stayed in continuous production essentially unchanged since 1950.