I see your point, yet TCP/IP's date of birth + 17 years doesn't equal the kind of internet adoption and use we associate with modernity, right?

Yea, the "we're so early" dog doesn't hunt anymore

Internet was created in the late 60’s

I don't consider "early" to mean "young". Actually, I would argue "early" in fact does mean "pre-mainstream".

Sonar: Internet and cellphones both took a few decades from first appearance to true “mainstream,” but the steep part of adoption was roughly 10–15 years once consumer use really started.