I'll put it this way for you; do you think if Dennis Lillee (debuted in early 1970s) were to be transported to the present (with a chance for only minimal adaptation), he would average roughly similar (say <30) to what he did in his day? The answer for me is, yes. And that is simply because the game had reached a level of professionalism by then which has by and large plateaued - i.e. it was a fully professional era back then, just as it is now. Now, if you ask the same question with regards to say, Clarrie Grimmett, considered one of the finer spin bowlers of his day, it would be an unequivocal no for me. I think he would he get destroyed. And that is not largely because his game was 'designed' for the conditions of his day, it is because he simply wasn't as professional - I think it's analogous with asking would a club cricketer if transferred instantaneously to test cricket average the same? No, they wouldn't. And before some annoying person pipes in, I am not saying Clarrie Grimmett couldn't be as good if he was raised in the modern era and had the same opportunities to adapt to the modern game. All I'm saying is it's impossible to have any idea of just how good he would be, when we are comparing eras where the standards where qualitatively different.