That's one way of looking at it. Another is that they did and they did leave traces which we attribute to another culture of which we don't really know the origins (which is in perhaps what became of the Sea Peoples - they bacame a culture we do know). Probably no way to ever really know.
They may indeed be the "dark matter" of archaeology, the mysterious invisible force that we don't understand but solves problems with existing theories. But I'm less certain than you that they are a figment of the academic mind.
Another is that they did and they did leave traces which we attribute to another culture of which we don't really know the origins
As I said, they didn't have a separate existence, and are not some otherwise unknown people. I didn't say they were a figment of imagination, only that they were not some forgotten people who then vanished without a trace (which is, quite literally, the conventional view). And it is easy to see this.