Which player threw away most of his incredible talent?

[Overrated]

For those that are knowledgeable about hockey history outside NHL, Boris Alexandrov and Yevgeni Belosheikin are two guys that I think have a strong case to be mentioned here.

What about Alexandrov? He seemed to have played in the top Soviet league until 27 or so. When he returned back home he played in the minors. Interestingly at 40 in the 90s he was still a competent player in the top Soviet league so he could have definitely achieved more in his career. What is more interesting is his minor league teammate Igor Kuznetsov who had near identical numbers to Alexandrov (slightly worse though) yet was stuck in Kazakhstan his whole career. In 1990 he played in Finland and was second in PPG.