Welcome to the buard...,
IMHO., it does not appear that economics nor the often cited lack of chromium in the Balkans was at play.
If one inspects the Yugoslavian made firearms they are of very high quality. The fit & finish is excellent. The features in the AK series of rifles such as receiver cover locks, integrated grenade launchers and sights., later bulged receivers and 1.5mm receiver thickness all seem to speak to high cost production in both the SKS and the AK type rifles.
As to why they chose non-chromelined bores and brass cased ammunition., is anyone's guess. Accuracy, history??
... and yours regarding Tito being the decision maker is now on the list.
