We also lived in caves for several tens of millenia across multiple stretches of time, without written language. There may have been some sort of ephemeral symbolic transfer (knots, beads, wood carvings,) but it looks like those cultures used primarily oral traditions. We know many non literate cultures develop memory palace techniques, so rigorous oral traditions can be incredibly durable and stable, with lots of information passed down accurately. All that to say, human tribes could have had detailed and specific knowledge of interactions with Neanderthals over millenia, and developed peaceful tradition that maximizes cooperation, or at least borders that kept conflict minimized. Neanderthals could likely do the same memory tricks.
5000 years is a blip - if humans find a sufficiently habitable environment, we apparently can settle for a pretty low quality of life.
It only works until it doesn't, though. Neanderthals or humans could have initiated an incident, in which traditions were distrusted or discarded or lost on either side, resulting in hostility, or they lost their elders to disease and the knowledge to survive.
Just like megafauna extinction, "bad humans were bad" probably doesn't come close to what actually happened.
Neanderthals were likely as or more intelligent than humans, implying susceptibility to all the same conflicts, biased thinking, and bad incentives that affect human cultures. It could be environmental or biological or a pure fluke that Neanderthals didn't outlive humans, but whatever the reason they're gone, it's going to be just as convoluted and nuanced as the rise and fall of millenia old human cultures.
Artefacts were left in caves because they're the only place where the artifacts can persist for hundreds and thousands of years, and ancient man knew this just like the modern man.
Cavemen are a trope, for sure, but there were cave dwellers, known as troglodytes. There were extensive periods of time where caves represented a really good solution to environmental and climate changes over the last 300,000 years.
Troglodytes were relatively rare, and most prehistoric humans were probably of the nomadic or small village types of hunter gatherer cultures.
There are plenty of caves that show evidence of long-term use of fire and burials, a good indication of habitation. However, it's true that caves were never a primary mode of habitation, just one that was convenient when it could be found... and pretty much the only one that we can see now due to differential preservation.
5000 years is a blip - if humans find a sufficiently habitable environment, we apparently can settle for a pretty low quality of life.
It only works until it doesn't, though. Neanderthals or humans could have initiated an incident, in which traditions were distrusted or discarded or lost on either side, resulting in hostility, or they lost their elders to disease and the knowledge to survive.
Just like megafauna extinction, "bad humans were bad" probably doesn't come close to what actually happened.
Neanderthals were likely as or more intelligent than humans, implying susceptibility to all the same conflicts, biased thinking, and bad incentives that affect human cultures. It could be environmental or biological or a pure fluke that Neanderthals didn't outlive humans, but whatever the reason they're gone, it's going to be just as convoluted and nuanced as the rise and fall of millenia old human cultures.