Multipart archives still exist. They're now used for file sharing websites that have a maximum file size. Before that they were for unreliable p2p networks, so you didn't lose the parts you'd already downloaded when your peer goes offline. Originally it was to fit something big on multiple cd-roms or floppies.
Opening somthing.rar also reads the data in somthing.r01 through somthing.r15 etc
Marshall has copyright on his lyrics, you just said yourself patents and copyright are different things.
Sufficiently different rip-offs that don't confuse consumers as being the original should be legal. They already are as far as copyright is concerned.
Many design patents should never have been registered, and should lose when defended in court. Design trademarks are a third similar issue.