The difference with Brunner (or at least the 'Club of Rome quartet' Brunner; he wrote space opera too) isn't so much the prediction rate as that he covered topics like racial tensions and pollution that other speculative fiction authors largely either avoided or covered through allegorical interactions on foreign planets.
Prediction wise, he got plenty wrong and iirc explicitly disclaimed that he was making predictions so much as incorporating contemporary analysis of trends. But more importantly, he was writing about economic growth in Southeast Asia and polluted oceans and trying to get his inflation and population growth forecasts right, whilst scifi norms involved continuations of the Cold War with robots and spacecraft dogfighting like WWII fighters, post apocalyptic scenarios or futures in which the World Government sent out ships to engage in trade and conflict with space bugs in far flung star systems.
Prediction wise, he got plenty wrong and iirc explicitly disclaimed that he was making predictions so much as incorporating contemporary analysis of trends. But more importantly, he was writing about economic growth in Southeast Asia and polluted oceans and trying to get his inflation and population growth forecasts right, whilst scifi norms involved continuations of the Cold War with robots and spacecraft dogfighting like WWII fighters, post apocalyptic scenarios or futures in which the World Government sent out ships to engage in trade and conflict with space bugs in far flung star systems.