It might be because we don't have consensus on the solution. Sounds as though everyone recognises there is a problem, but we have many different suggestions about how to resolve it. Some people think more rules are needed, others think more users need to be banned, some say lock the board completely, while others still think more moderators will help. Even I'm starting to wonder what would be the most effective fix.
Some of those options are offered as alternatives only because nothing is being done, e.g. lock the board if no one's gonna fix it, or clarify the rules if that's what's stopping mods from cleaning it up. I don't think there is much disagreement that the shitty copypasta needs to be removed one way or another.