You're signalling a ton of confidence about a politically loaded topic and claiming that self-serving bias is keeping a mainstream academic field, of which you are an amateur, from seeing the truth about a central question in their field.

Take the outside view about yourself for a minute.

Anyway, economics in the Soviet Union barely resembled Western economics and Marxian Political Economy really shouldn't be considered a part of the economic establishment you're critiquing. To the extent there were talented Soviet economists trying to make an impossibly flawed system succeed is poor evidence of self-interest bias. But that really isn't the point: the point is that economists generally minimize the roll of policy-making relative to other opinion-makers. You can say they're just following the evidence in those cases but then you're getting awfully close to "they're following the evidence when they agree with me and are biased when they don't agree with me".