Speaker cable and Interconnect BRASS Connectors

I have been thinking about speaker cables and interconnect connectors, in that cable manufacturers don't say what the connectors are made off. When you read the description of cables you are lead to believe that the cables the best thing there is since slice bread. Yes I do know that cables make a difference in your system but i don't understand why the connectors in most cases are made of BRASS. Don't you think Brass will cause a bottleneck in signal flow? if you consider what the best electrical conductors are you might agree:
1. Silver (pure)2. Copper (pure)3. Gold (pure)4. Aluminum5. Zinc6. Nickel7. Brass8. Bronze9. Iron10. Platinum11. Steel
Brass falls in 7th place; so why make the connectors out of Brass? I think we are paying $400 + for speaker and interconnect cables but not getting the full potential of these cables because of the Brass connectors. And don't tell me that the Brass connectors don't affect the signal negatively. You know about the difference that silver solder makes, then what about Brass? have you tested it against other connectors such as copper? I am curious to hear your thoughts.