These clefs come from “autograph copies” of each composer’s music — versions that they handwrote. Each is just an example, not necessarily how a composer always wrote. And the composers themselves were chosen just for flavor, rather than for any particular scientific or historical reason.
The chart above shows a mix of personal quirk and the evolution of a standardized mark over the course of a few centuries. As Smithsonian notes in its history of the sign, the treble clef evolved as a representation of the letter G (which is why it’s also called the G clef, since it indicates that the line it appears on is G1). It probably began to appear in the 17th century, though other sources dispute the exact timing and origin, with some placing it as early as the 13th century).