In full-Apartheid-heyday SA, American instruments probably weren't so easy to come by due to the sanctions and the strict SA foreign currency management ("Financial Rand", they had a virtual currency for imports). Japan, otoh, never had issues dealing with Apartheid SA, they sold a lot of cars there.
But you're right, come the latish 70ies, Ibanez was pushing hard to establish itself as a brand and they were very successful at leaving the "law suit"-image behind them. Lots of professional German bands played Ibanez around that time too - ones that could have afforded Fender or Gibson with ease.
