I don't think Van Gogh is a good example. There are certain artists whose work outlives them by centuries, not many, but we still talk about Michelangelo, da Vinci, Monet, etc. The rest of your post is accurate, though.
No one really cares.
We simply haven't had enough time pass. Eventually, some day, people will forget who Julius Caesar was. It may take 50,000 years. It may take 500,000. They'll forget.
We do have more insight into ancient Egyptian pharaohs and architects, however, as these details were more carefully preserved.
That being said, I'm sure 500K years from now, these details will all be buried on some thumb drive in an underground archive and our descendents will lack the drivers to decode them.
Unless the humans figure out reliable ways for them and technology to survive multiple nuclear world wars
Which doesn't seem impossible, not at all
[1] https://knowyourmeme.com/memes/complaint-tablet-to-ea-nasir
what does it matter if you're forgotten after 5 years or 50,000
It isn't as if you would notice anyway