That’s how some of these generational boundaries blur together, where the experience that defines one, can already have been part of the previous in specific circumstances.

Definitely. Especially when you go out of your way to learn or experience things more commonly associated with different generations. Personally, I didn't ever really need to learn DOS or Win3.2, but because I loved computers from a very early age, I spent a ton of time learning about computers from very early on. Now it means that I understand computers and technology way better than my contemporaries that are more traditional Millenials (and don't even get me started on Gen Z and their inability to understand basic folder/file structures).

That applies to technology, music, films, books, etc., especially since the internet has completely changed the way that people find, learn about, and consume media. It's kind of tangential, but if you want to hear a great example of the effect of internet on music culture, just listen to the song Losing My Edge by LCD Soundsystem for the story of a Gen Xer whose encyclopedic knowledge of music briefly made him "cool" in the early 2000's until all the Millenials started finding all the stuff he experienced firsthand.

And personally, I’ve VERY interested in seeing 10 years down the line when we have the first adults who grew up with on-demand streaming and tablets/phones.

Yeah, I've already noticed some generational differences with my own kids and some of the students I teach. They seem to be simultaneously less patient and more patient. Less patient because they are used to always being able to watch something of their choosing and change shows whenever they get bored, but also more patient because everything can be paused as is available on-demand, so they have no problem waiting for a more opportune time to watch something as a group (and with my kids, we only started to let them use tablets after they turned 5 and then only on road trips).

It's also interesting because the cultural zeitgeist is a lot less monolithic. Instead of everyone watching Ninja Turtles or everyone listening to Nirvana, kids have developed their own little niches and shared interests by watching whatever piques their interest. Anecdotally, it seems like it's resulting in a lot less of an "in-crowd." Even though there are still "the cool kids," the cool kids have known shared interests with the uncool kids, so it's lot more like a web than a hierarchy. In my very limited experience, every day is like the end of The Breakfast Club, albeit still with plenty of drama and cattiness.