mother necessities

What does the phrase, “necessities are the mother of invention” mean? Please include at least three good examples to support your thinking.

I think that this phrase means that if there’s a need then somebody will invent it. For example, there was a need to make cotton faster, so somebody invented the cotton gin. Another example was the telephone. There was a need to talk to people faster than going over to each others house, so the telephone was invented so people could communicate a lot faster. Also, it took a long time to make clothing, because it was being sewed by hand, so Elias invented a sewing machine that could make the product a lot faster.