I'd love to see some sort of cultural analysis of it.
I have a few pet theories.
I think part of it is we were marketed to for action figures specifically and relentlessly
This is part of it, for sure. Shows were created to sell toys in the '80s. Literally. They still merchandise cartoons and movies, but they aren't designing toys first and creating storylines after. Secret Galaxy did a great episode on why:
Spoiler: as with most bad things in America, it can be attributed to Ronald Reagan.
where their world is all streaming, on demand, bespoke/niche.
This is another piece. There used to be four TV channels. Cable TV—and later the internet and YouTube—led to the death of monoculture. It's easier to sell toys when every boy under 12 is watching one of five shows.
They go from little kid toys to digital games
You're alluding to the biggest cause IMO: video games. Previous generations had no choice but to go outside and play.
I'm sure kids today are still bored, but they have 1000 times the options I did as a kid, even 20 years ago.
You have TV, countless YouTube channels, social media, and countless video games. For almost every kid, there are thousands of great options to occupy their time before they arrive at "play with a physical toy."
I've got one niece and one nephew who will literally play with toys, like if they don't know you're looking you'll see them creating stories and dialogue with action figures or dolls, sometimes together. My brother really works to not inhibit that because he wants them to have imagination.
This is the last piece. From what I've seen, parenting has become a lot more hands-on than it was when I was a kid. I'd say 80+% of my free time was spent alone. I loved it. It allowed me to develop an imagination and learn to entertain myself. Would I have a better relationship with my parents if we spent more time together? Probably.
My friends with kids spend the vast majority of their free time with their kids. They go to the park, watch a baseball game, and even play with toys together. I'm not saying it's better or worse, but it is different.
until he discovered he's good at baseball and I literally haven't seen him for more than a half hour since April because he's got games and practices seven days a week).
Youth sports becoming a cottage industry is so gross. I played youth soccer as a kid. We practiced and played a game once a week. It was a four-hour commitment, all done at the park 10 minutes from my house. Today, parents with kids in sports have no free time. It's not better for the parent or child.