As per others, what is impossible? Certainly if you play a few hours per day (and many do) attaining low level 80's is easy.
Getting to TM is easy with the improved equipment (and assuming you are playing a lot and learning all the shots, greens and course management, then an average of 66 is very attainable. Many have made Legend by that stage.
Conversely many would say with the improved equipment and you have taken the time to learn the game, that not getting to Legend by level 90 is impossible........