I've always been confused as to why the super states of the eastern Mediterranean utterly collapse all around the same period time. I know the "Sea People" invaded and raided ports and decimated the region and that has been the historical consensus for years, but was this the only cause? I'm also aware of the idea that the "Sea People" attacking them opened up opportunities for other tribes to attack the more inland settlements of these empires. I guess I'm just curious if there are other theories of why the peoples of the region collapsed or if they were in decline before the "Sea People" came and the invasions of other tribes.
There's always more to be said on the topic, but check out the AMA with Eric Cline who wrote a book on the topic. Also, I touched on this, focusing particularly on the Hittites, in How did the civilizations fall in the end of the Bronze Age?
The collapses (or lack thereof) and the concomitant changes that occurred at the end of the Late Bronze Age affected different parts of the eastern Mediterranean in rather different ways and quite probably occurred for slightly different reasons in each region, so it is important to study each on its own terms. Put a different way, the reasons that caused the collapse of the Hittite empire are not necessarily the same as those that caused the contraction of the Assyrian empire or the collapse of the Mycenaean palatial system, linked through trade and diplomacy though they were.
It is important to note that the "Sea Peoples" were not one group but several distinct groups originating in different areas of Europe and the Mediterranean and settling in different regions at different times. I wrote more about this here and here.