First of all since this was about scores, the Old Course and many other links courses are designed along the sea and in places where the wind and elements are blowing like crazy all the time making hard fast conditions far more difficult. When these great scores are posted in most cases it's when there are benign conditions. When you see them super low on the PGA tour in most cases it's right after some wetter weather and the greens are soft and perceptive, some times they are even placing it in the fairways and again weather conditions are benign.
Occasionally there are and will always be amazing rounds where guys are spot on and holing every single put. Want to change that, simple disallow anchoring...(oh wait, they've done that already :p). Now only the really good players will make low scores.
As for the athletes, not sure if bigger stronger faster is the case but certainly healthier, fitter and easier access to mental coaching helps, no doubt, as does improvements in the quality of instruction, computer analysis, new bionic equipment and balls that fly miles.
John, the Asians win not because they are better athletes, I don't believe that for a minute. However, they more focused, don't let other things in life distract them, start disciplined, regimented training routines that effectively cause them to forgo childhood activities etc at young ages and are brought up focusing on 1 thing and one thing only. Complete and total commitment, while US women also want to be girls, go to school, have fun and in general are brought up in completely different, far more luxurious pampered conditions.
Wait until some of our female soccer talent starts switching to golf, different mentality than the big break/model wannabe who chooses golf because she couldn't catch a softball, dribble a basketball or kick a soccer ball, plus the country club has a cool pool and is full of cute guys.