im just saying that its nice to have the OPTION of either reloading or buying factory ammo. options are good.
case in point: several springs ago we were shooting groundhogs. i was using a .223, my friend a .243, and the third guy who wed just brought along was using some obscure caliber (i dont even remember what it was). we ended up staying for 2 extra days because the weather was amazing (groundhogs really come out on sunny, wind-free days). both of them were out of ammo (i always bring a couple hundred rounds of .223 so i was good)... so a trip to the local CT, .243 guy was out the door with some ammo he found on sale. the other guy was SOOL and had to use an old Sears .22LR for the rest of the hunt. he got one groundhog with it and was cursing nonstop for 2 whole days.
so you can never foresee every situation. the guy came with 4 boxes of ammo that he was sure would be enough, and it wasnt. what if you forget/lose your ammo? what if you end up hunting longer than you had foreseen? yeah its easy to say 'that will never happen to me', but you never know. i personally would not go out and buy a gun in an obsolete caliber if i had a choice.
if someone gave me a .243 WSSM i would probably keep it, but if you are planning a new firearm purchase why not choose one of the dozens of other popular calibers out there that will be around 20 years from now and have widely available factory ammo and brass? and its not like the .243 WSSM has some earth-shattering ballistics that cant be matched by something else.