Disillusioned JW:
Daniel was probably speaking of eth[n]ic groups rather than kingdoms when he said "the Medes and the Persians".Probably. It is also possible that both were listed because both the Medes and the Persians (as Elam) were mentioned in Jeremiah’s list in chapter 25.
it depends upon the purpose of of why Daniel wrote the prophecy
There’s no evidence the author of Daniel wrote any ‘prophecies’ at all or that ‘prophecy’ (as distinct from predictions based on other methods such as speculation, trend analysis etc) is even possible. Though presented as ‘prophecy’, obvious references to the Seleucid period and the overall purpose of the book negate any need for any reliance on such superstitions. The purpose of setting the events in the Neo-Babylonian period and phrasing the stories as ‘prophecy’ helps reinforce the parallels between Babylonian and Syrian oppression.
But, I noticed it is many pages long and I am not yet interested in reading all of the pages.No problem. Unlike ‘scholar’, I don’t imagine anyone is obligated to read anything in particular. In brief, the first few pages indicate early interpretations by various ‘church fathers’. More generally, if there were in fact any such calculations at the time that the ‘70 weeks’ pointed to the ‘messiah’ appearing some time around 30CE, you would reasonably expect to see it directly stated at least in Paul’s writings and the ‘gospels’. Instead, what we find is exactly what we would expect to see from a made-up history only loosely based on an actual person: almost no biographical details of Jesus from Paul, more detail from the author of Mark but no genealogy, fleshed out (but inconsistent) genealogies from the authors of Matthew and Luke, and more anecdotes about Jesus added by the author of John (noting that all of the ‘gospels’ are actually anonymous works that were only later traditionally accredited to the named authors).