In the pic comparisons the buckle on the Madden is more of a circle while the buckle on the Ringo has more squared off corners. That may have been intentionally to make it harder to make a claim.
I really think more of their protection would be within patent law or trade dress under Trademark law vs. copyright. Patents are extremely expensive to obtain and maintain and I can't imagine these designers are filing a patent for every shoe or piece of clothing they have ever made, are filing those patents in every country worldwide and then paying law firms to maintain those patents annually. That would be so expensive (and patent lawyers are some of the most expensive to hire) but maybe that is part of why the goods cost so much. Even if they could I can imagine that at some point they have to make a business decision on if it is worth the extra multi-millions a year of legal costs (on top of the cost of going to court to defend every shoe, shirt, suit) trying to prove claims (and prove that your design was not also 'inspired' by designers before you) to restrict the Maddens of the world.
I'll have to do lunch with some of my colleagues in the patent department and pick their brains.