The industry is much less focused on what it can gain through litigation, and much more focused on what it loses by not aggressively protecting their copyrights.
I recall a conversation with a friend who managed PR for the RIAA when they went around suing teenagers for using P2P (yeah, imagine that PR job). They knew the mess it would cause, but they had to do it, because it sent a stronger message if they did nothing. IANAL, but there's something about if you knowingly let someone use your copyright without demanding they license it from you, you give up or lose the copyright at some point? (Edit: apparently this only applies to trademarks, not copyrights)
Labels have invested a heap of cash buying these rights, we shouldn't all be shocked when they act lawfully to protect them.