I'm not sure that you could say that Raleigh ever consistently made premium quality bikes. I own four early 70s Raleighs, and although they are all great bikes, every one of them has evidence of poor quality control at the factory. Specifically, some brazed joints have too much/too little brass; original paint has flaws; and on one of the bikes one of the chainstays is about a quarter inch shorter than the other (compensated for by the horizontal dropout). That said, they were probably no different from the other large production companies.
Also, I have to say that the quality of the headset on my 72 Super Course is amazingly good. Close to 50 years on this thing and it shows very little wear, which is a good thing because it's 26 tpi and would require a fork replacement if it went bad.