The amount of industrial engineering required to make a ballpoint pen is quite substantial the click mechanism isn’t the impressive part making balls which are dimensionally accurate to 0.1 micrometer is the challenging part.
Without that level of accuracy you can’t make a ballpoint pen and without it there is no real advantage of making the click mechanism.
And making these balls is very challenging even today. These are often still used as an example for manufacturing deficiencies in places like China as whilst they tend to make the bulk of the ballpoint pens they still have to buy the balls form German and Swiss manufacturers.
Hmm, there are retractable fountain pens like the Namiki Vanishing Point, and even Sharpies that are retractable. I think it'd be fair to say the clicky ballpoints represent an excellent combination of cheapness and usefulness, but they don't have a monopoly on retractable points.
Without that level of accuracy you can’t make a ballpoint pen and without it there is no real advantage of making the click mechanism.
And making these balls is very challenging even today. These are often still used as an example for manufacturing deficiencies in places like China as whilst they tend to make the bulk of the ballpoint pens they still have to buy the balls form German and Swiss manufacturers.