Not even a speculation ?
You asked for it...it is strange to me that a company will use another companies name in their products. Example, I am looking for a Steyr Jeff Cooper in Winchester .308. Seems like they are promoting Winchester. If I had a Bruz 9mm gun I would not come out with a Bruz chambered in .357. Hmmm, the "Bruz 9". Kinda has a ring to it.
I asked several folks at Carl Walther and related to Carl Walther about the P99 .357 Sig barrels. Earl or Earl's Repair Service requested that Carl Walther make some prototype barrels. Yes, factory .357 Sig barrels exist, but the number is unknown (and probably low), and Earl has them all. Irv Stone of Bar-Sto had a chance to try one out.
Be thankful that Carl Walther developed the .40 Auto P99, because it serves as the platform for the .357 Sig barrel that Bar-Sto is about to release.
As far as the .357 Sig's days being gone, I cannot agree. I can buy .357 Sig ammo for the same price as .40 Auto. If you are a smart shopper, it's not expensive. Most gun shops may charge more because they don't buy as much, do not get a deeper discount, and thus cannot pass along the savings to the consumer. Buy in bulk.