If thats the criteria then, well, none of the tech you listed is revolutionary either.
Automobile: we already used horses. Cars were just us moving faster and longer.
Radio: we already could send messages wirelessly via sound waves. So this was just doing it with another wave.
Airplanes: we already had hot air balloons. Putting a fan on the front to move isn't a big change.
Etc...
Correct. On their own those technologies weren't that big of a change. But if you combine radio, television, telephone, automobile, airplane, automated manufacturing, home appliances, it becomes a very significant change to human society in that era. We were comparing that era to the modern era. I specified that the era and time period represented a period of new useful technologies and impactful change to society, as compared to recent years in which it has been less so.
tom i hate to burst your bubble, but people born in the first half of the 20th century didn't actually invent books, libraries, and post offices. those things have been around for some time.
I did not claim that the early 20th century invented language and the written word. The invention of language and the written word was arguably even more important than the revolutions to society between the early to mid 1900's.
Humanity has been making less important revolutions and inventions as time goes on.