How you can honestly think that when more people are playing golf the quality of players stays the same? Do you think that personal trainers, dietitians, swing coaches, video analysis, ect.... hasn't improved the quality of players?
But it also reduces the incentive to play any better than is required to get a decent payday. When you can keep your card and make a more than comfortable living while hanging at number 100 on the money list, there is no survival incentive. In 2010 #100 was Greg Chalmers at $989,415 - almost a millionaire in one year, and only the most vigilant TV viewers have ever even heard of him. #100 in 1980, Peter Oosterhuis, made $35,612. In 30 years, Chalmer's earnings were 27.8 times what Oosterhuis made. No way that simple inflation can account for that. Unless a player has an unusually strong competitive streak, he is going to lose some of that drive to win as soon as the money starts rolling in. It doesn't matter what he consciously wants if he has lost that subconscious hunger which is needed to continue to play at his absolute best when the conscious mind can't see a need for it. Add to that the inevitable distractions that come with quick success and you have most of the top half of the money list in today's game.
During most of Jack's career, #100 didn't keep his card and didn't make enough to go out for a dollar meal at Mickey D's. There was a deeper need to win.
I'm not on either side in this argument, because I'm in the camp that believes that there is simply too much that is different between the two eras to make any sort of true comparison. Both are the best of their time. But I can refute some of the attempts to argue things like field depth. The variables simply do not support the validity of such comparisons.