I read mostly books written before the World Wars and I’m doubtful there’s much after that period of any real and lasting value. That doesn’t mean I don’t enjoy some of it, of course, mostly the fiction. The exception might be really niche works of local history, which is probably <0.001% of all such books, or a few really good scientific/mathematical compendiums.
It means books get written now which explore perspectives and voices unheard before, which in turn can help us readers expand our frame of reference.
The collective works of fiction written before 1900 tend to reflect the societal viewpoints of well-off white men (even when written by women or specifically dealing with societal ills). Go a few decades beyond that and you see authors from a working class background join the chorus, then more women, a broadening of sexual themes reflecting society's change (feminism, sexual liberation, homosexuality, etc.), more open criticism of religion too. Digital technology changed society significantly, and this is of course reflected in writing from the more recent decades, and coming up towards today you see more and more diversity amongst authors, adding — through the characters and narratives they create — yet more perspectives and insights. Sometimes pushing the envelope of a specific field, sometimes getting rid of tropes which no longer convince. Fiction changes constantly and will always be rooted in the year it was written.
You sell yourself short if you stop at 1940.
Two Americans today, whatever their sex and race, have virtually everything in common with each other compared to anybody from 1800, let alone 800. The extreme, excessive focus on race and sex in contemporary writing is exactly what makes it boring and irrelevant. This comment is a great example - you've been taught by contemporary writing that such a tendency existed, when it in fact excludes the objective reality of the tons of works that could not have been said to be "written" or "about" such people even by modern framing, but also the fact that "well-off white man" is a completely meaningless and inapplicable phrase if you go back more than a couple centuries.
The sort of work you're describing is the stuff we're taught to acculturate us to the world we already live in. There's no point browbeating me with even more material that I am already steeped in.
Define "virtually everything"?
The rich, white, and men have had massively different resources and societal privileges in each of those eras.
Even today it seems obvious to me that to be rich or white or male each brings benefits at every stage of life which can drastically change ones life experience: food security, personal safety, education, job prospects, and romantic opportunities.
I think people still write good books which can provide good insights into the human condition, it's just hard to find them in the present.
https://www.goodreads.com/list/show/21995.Best_21st_Century_...
People have had interesting insights in that period - of course - but very few of them require anything longer than a sentence, and they are few and far between.
By the way, 2000 was chosen semi-arbitrarily, I would probably put the line much farther back.
I do think, as time goes on, and things are declassified, we'll learn more about e.g., the Iraq War than we know now. To a point, things become clearer with distance, which often renders books written on contemporary subjects outdated. But a book published today could be a decent summary of events for people who didn't live through them, or were too young to pay attention at the time. Unfortunately, one recent why I don't pay them too much mind is that most of the genre is hopelessly partisan, one way or another, and I don't know that there are any really great historians to write something timeless. But either way, I would say the insights you can glean from those books are still readily available if you're watching events critically today. Not much has changed, and if it has, it was usually for the worst. Maybe the most interesting part for many people would be the reminder that many of the same people directly responsible for those disasters are still considered respectable people today and help drive policy. E.g., Bill Kristol didn't go into some kind of exile - he's still considered a very serious person and has a lot of influence and is out there shilling the same type of thinking in a different context.
Crashed, by Adam Tooze was a very very good retelling of the GFC, and I did read all the newspapers at the time and still found lots of interesting stuff.
More generally, I'd argue that modern historians probably have the highest chance of producing useful new insights recently.
If you accept fiction (and like fantasy fiction), I'd argue that the Malazan books of the fallen and/or the Nine Worlds series are serious works that are going to endure. Ask me again in a century, though ;)