Quick thought:
While it is true that sharing your wealth is a potential disincentive to earning it, the primary issue of socialism/communist government structures regarding productivity is that it removes the process of creative destruction. More aptly that central planning can stay on a narrative even after that view becomes obsolete.
This is most easily expressed in capitalism and its close relative anarchy, which unfortunately creates inequality. It inherently lets winners ‘win’ and rule the day. What is interesting however, is that ‘listening’ to creative destruction can also take place in countries that redistribute wealth.
Countries such as Scandinavian ones and also even China, Japan, some socialistic Asian tiger economies, also New Zealand are potential examples. They have moved ‘on a dime’ in terms of policies, updating and stretching policy frameworks, during growth phases or paradigm shifts to correspond accordingly. while also having policies of redistribution.