Have you noticed that your inability to just “read a book” differs by genre? I suffer from that with pretty much any fiction, but can still lose afternoons reading a well-written history or scientific explainer.
Not op, but yes. It is not just difference in genre. The books that appeared to me as awesome when I was younger are completely uninteresting now. I try to read and switch into twitter within three pages.
But, once in a while I run into completely different book and cant stop reading it. Books that I would find boring back then I think. Like you, I read way more well-written history now, but there is also occasional fiction.
I think that the big difference is that once you are well into adulthood, it is much harder to come across book recommendation that suits you. The market is dominated by youth needs I guess.
The market isn't dominated by youth needs. It might seem that way because your selection shrinks over time, but try this model:
Finding good books is a multi-armed bandit problem, and most of us follow intuitively a strategy well suited to that - explore (figure out which levers to pull, or which kinds of writing you care about, by randomly pursuing) and exploit (pick things that you know to be good because you spent time evaluating).
As you age, you're becoming more discerning, because you now know better what's possible, and you know better what suits you. But since the landscape is, for practical purposes, infinite, you also face the hill climbing problem of local maxima. That's why picking new random books in different areas works - it allows you to get "unstuck", and possibly find new maxima.
This also means - sorry - that at some point "well-written history" won't really do it for you any more, either. You'll have explored that landscape enough to become stuck on a local maximum. It will be something like "I really enjoy books about 1600-1800 by these five authors, it's just the best". And then you've read all those, and hopefully something entirely different crosses your path.
That sounds like awful lot of work for very little gain.
Which is exactly the difference between market that is dominated by people like you and the one that does not. I don't need to go out of way to explore to find tv series I will like. That market is clearly dominated by people like me.
That is how humans behave instinctively. It isn't work. It just happens. The same will happen to your TV series. At some point, you'll like different stuff.
It also isn't "little gain" - it's the most efficient approach to the multi-armed bandit problem. Other approaches are less efficient.
Or, have we become boring? I've noticed I have outgrown some things I loved as a young adult, like most videogames; though I don't know if it's just me being anti-commercial stuff, trying to avoid becoming a pay-to-win customer, and more of a buy-once customer.
It’s okay to move on. Maybe you not liking videogames is boring to those who still enjoy them? I’ve moved on from most games and it feels like fresh air, in part because I used games as a generally-unhealthy escape (as one might do with alcohol, I now play games in celebration rather than habitually or to escape emotions). It feels healthy to reevaluate how I spend money and time.
But, once in a while I run into completely different book and cant stop reading it. Books that I would find boring back then I think. Like you, I read way more well-written history now, but there is also occasional fiction.
I think that the big difference is that once you are well into adulthood, it is much harder to come across book recommendation that suits you. The market is dominated by youth needs I guess.