I'd disagree with the notion "it has to". The chilling effect on a large number of new wiki contributors could be considered more detrimental than weakening sock puppet protection. (IE if a huge country suddenly started jailing people who make edits not considered state-approved)

I suspect there are plenty of ways to allow new accounts to make edits on a smaller subset of articles until they have passed some threshold of trust which could minimize the sock puppet abuse.

Point is everything is a give and take.