It's true that SA would need a huge talent boost if they are to be competitive by the next world cup and yes there aren't many NRL/ESL players with SA heritage running around (that I know of), but there is a huge amount of very talented SA RU players who could quickly learn the ins and outs of RL, that are on contracts worth peanuts compared to what your average NRL player is earning.
If the RLIF really wanted a flood of SA talent they could easily get it by pressuring the NRL into allowing limited cap exemptions for SA players, add in a few well placed heritage players and we'd be off to the races.
If they used this tactic I wouldn't be surprised to see the Rhinos go from international RL bottom dwellers into the top four international teams in the world by the next WC, I also wouldn't be too surprised to see an ex-Springbok or two playing for the Rhinos either.
But I can't see any of this happening, it'd be risky and I doubt that the RLIF has the balls to attempt such a plan.