Columbus didn't discover America, Edison didn't invent the light bulb, and the Wright Brothers weren't the first to fly a plane. But they are all generally given credit for being 1st because they actually found a practical use for their discovery or invention. The first guys to America didn't send anyone back, and the 1st light bulb and airplane inventors stuck their ideas in a drawer and did nothing with it. Columbus inspired settlement and Edison and the Wright brothers continued to refine and market their ideas.
Glock wasn't the 1st to come out with a plastic gun, but very few will know that minutia. HK was first, but that weapon is a foot note in firearms history.