I suspect that , as much as anything else, there is an inability to educate folks enough for them to safely use smokeless powder. If there were only one powder it might be possible. There is really no difference in the steel in the barrells, but there are tremendous differences in powders. Black powder, and substitutes are of course measured by volume, whereas all the smokeless must be weighed, and carefully. A little can go a long way. I'm not familiar with the Savage, but I would bet that there are only certain powders that can be used. I would think that charges should be weighed.
Can you imagine the result if some knucklehead substituted something like Bullseye? A three grain charge of Bullseye is a pretty good load in a 38, yet it is possible to overcharge the case several times in volume. A mistake could mean death. I believe it is this which keeps the companies away from offering smokeless barrells more than anything.