The book of Joshua describes the allotment to Simeon in terms that give away the outcome in advance: the inheritance of Simeon lay within the inheritance of the children of Judah, because Judah's portion was too large for them. The towns listed are in the dry south, Beersheba, Hormah, Ziklag and their villages. A tribe holding towns inside another tribe's territory has no border of its own to defend and no natural line of separation, and within a few generations the record treats the area simply as Judah.
The numbers in Numbers tell the same story. At the first census in the wilderness Simeon is counted at fifty nine thousand three hundred fighting men, one of the larger tribes. At the second, taken a generation later, the figure is twenty two thousand two hundred, by far the steepest fall recorded for any tribe. Between the two censuses stands the episode at Baal Peor, where the man killed by Phinehas is named as a prince of a Simeonite family, and a plague follows. The text does not link the numbers to the story explicitly, and the arrangement of the material invites the reader to.
Moses' blessing in Deuteronomy 33 goes through the tribes one by one and omits Simeon entirely.
What remains is genealogical. Chronicles preserves Simeonite clan lists and records groups pushing out toward Gedor and into the hill country of Seir in search of pasture. The prophecy at the deathbed said scattered in Israel, and this is what it looked like in practice: not exile or destruction, but a name that stops being a place.