Curious if you mean nearsighted people or all people needing glasses. There are tons of farsighted people like myself that need glasses to live in our modern society to get by, but wouldn't be significantly impacted even just a few hundred years ago if we didn't need to read or work with things on a small scale. I can see the stars just fine without my glasses. Additionally as people age they tend to need glasses as well and today people are living longer generally, so that is also creating more need.