Someone asked a question about how frequently young people have time to socialize and it made me think about what people do with their evenings. I recently asked my son to go to a concert (free ticket to see a band i know he likes) and he declined because it was an hour away on a weeknight. If we invite our kids or niece/nephew to dinner they always want to go at 6/630 which feels so early. Edit: Kids are 30ish.
That was 10 years ago. The further we get from “the 1900s” the broader the term will become to include the whole century, much like the 1800s is 1800-1899. I imagine in another 10-20 years it will be more and more common to see this shift when referencing past events.