I belong to the generation who flipped switches to enter a boot program. In the early 1980s, I worked on a microcomputer called Micro-78, developed by Electronics Corporation of India Ltd (ECIL). It was a sort of clone of Altair 8800. I distinctly remember what happens when a small boot program was entered using the toggle switches and executed by pressing a button. The program reads a second boot program contained in the 1st track of the floppy disk and overwrites it on itself in such a way that the second boot program starts executing to load a disk operating system. I think the term "bootstrap" refers to this process of the first boot program reading and overwriting the second boot program on itself, in a way "pulling itself up" with the additional functionality of the second boot program. That may be the origin of the original meaning of "the bootstrap program".