No problem at all. See Russian example. 10 years ago it was 50/50% Visa/Mastercard on the Russian market. Today it is like 30/30/30 Mir/Visa/MC (Mir is the national payment system). And even those 60% are not "real" Visa/MC, since they are being processed through a centralized platform, owned by the Russian Central Bank. For example, it helped to save all the cards in working condition when Visa/MC exited Russia