I'm a customer of spamcop and I turn in my spam so the originating IP will be added to their blocklist, and I do it very enthusiastically.
ISP's who are known to disregard spam reports and complaints are known as "spam friendly", and yes, there are more ISP's than we realize that are taking action against spammers. My remedy is to keep reporting spam and to use Spamcop's blocklist. I've found that not only am I not missing any e-mail, I'm getting a lot less spam that I have to wade through to find the one e-mail I'm looking for.
Please note that most people who post here in the forums are users that choose to help and not employees of Spamcop.