Put quite simply the economics do not work when you can buy a tack driving Ruger American 30-06 for $450 and a pretty nice original 03A3 for $750.
The cost of the current reproductions previously noted would indicate to me that a milspec 03A3 for example would be so high no one would pay with no military pedigree or chance to appreciate in value.
It does seem the cost/benefit equation is balanced to the point that replacement barrels are coming to market. Perhaps in time it could be profitable for
complete rifles. The example of the reproduction Ford Mustangs comes to mind.