It's not like the Winchester/Browning creation of the 7wsm or the 243 wssm.
The .243 WSSM may not be dead. Winchester is going to make brass for it again this year, and it's rumored to maybe show up on the market again in the platform it should have been introduced in the first place. AR15.
Olympic Arms may be the guilty party I've heard from the guys machining the barrel for my new upper in that caliber.