Michael Rydelnik and others argue that the idea that Ishmael is the father of the Arabs comes from the Koran and is not a correct teaching (see https://www.michaelrydelnik.org/blog/thoughts-on-antisemitic-terrorism). The idea, however, originated with Josephus.
Most commentaries borrow information from previous commentaries (or Josephus) and continue the assumption, if that argument is correct. But what about you? Do you think there is good reason to believe that Ishmael actually is the father of the Arabs?
Discussion
NewSome hints
I think the author confuses "does not explicitly say" with "there is some good evidence". For starters, there are some marked DNA similarities between the Arabs and Jews, suggesting some relationship as would exist between brothers. Of course, you've got that a generation closer with the Edomites and Jews, as well as with the other children of Abraham in the same generation.
Then you have the fact that they settled (Genesis 25) from Havilah to Shur, and Psalm 83:6 makes a parallel of "Arabians" and "Ishmael", and 1 Chronicles 27:30 notes an Ishmaelite was in charge of the camels, the camel caravan of the Ishmaelites participating in Joseph's slavery in Genesis, and the like. Plus, it is a custom among the Arabs to recount their (at least hypothetical) ancestry a long way back--so both Josephus and Mohammed were probably pointing to that as well.
Absolute proof? No, but the Biblical descriptions of Ishmaelites--tents, camels, caravans, and the like--sure look a lot like the Arabic peoples to me.
Aspiring to be a stick in the mud.