alt Hacker NewsThe Fall of Civilizations Podcast (nice one) had an episode on this topic.
According to it, the sea peoples could instead be vast numbers of western europeans fleeing the outcome of a massive volcanic eruption in Iceland, which would have triggered crop failures and mass starvation in western and northern europe.
A significant portion of the survivors would have fled en masse to the richer eastern Mediterranean empires, thereby causing their downfall.
Cam here to link this. Such a great podcast series.