Kasonen wrote:
Why would someone argue that in Revelation 16 a similar thing will not be literal?
Because the text of Exodus 7:20 is not literal either but based on the Haggadah, the Passover story that is told during the Seder celebration.
It was once believed that the Haggadah was written after the Exodus account. And it is true that modern versions are. But the one you read in Exodus is based on an even older version, maybe oral or maybe written, but obviously from at least two combined sources. One can find two or three different Haggadahs quoted in the Bible from different periods, especially if you use a Catholic/Orthodox Bible and read the last chapters of the Wisdom of Solomon.
But Exodus and Psalms have different accounts of what happened and tell different stories too. Psalms 78 & 105 say there were only 7/8 plagues and not 10. The two idependent versions from the Psalms were interwoven into the final narrative of the Torah after the Exile from Babylon, not before. These stories are older than what came to be the Psalms themselves.
When Exodus was composed, the narrative section was developed to teach Jewish people to celebrate the Passover with a story--the Haggadah--in order to hold a Seder celebration. At first, as early as the time of Ezra, priests wrote a part, but then, even later, non-priests added to it, and we went from the 7/8 to 10 plagues concept we know today:
The Non-Priestly account lists eight plagues (blood, frogs, arov, pestilence, hail, locusts, darkness and death of the firstborn) and the Priestly source has only five (blood, frogs, lice, boils and death of the firstborn).--How Many Plagues Were There In Egypt? Suprise!, Haaretz, April 9, 2023.So if the first plagues came from sources which were not literal, then it is not likely that a book that calls itself an "apocalypse" in the first verse of its own writing is describing anything that we would expect to literally happen.