if there's a wider problem presumably people will be aware of it.
Most ISPs do now offer spam filtering, but in some cases you have to opt in to it - or even pay a small fee for it. With respect, although you might not want people to suggest anti-spam measures that's exactly what you need to put in place. Whilst you might think (with some justification) that ISPs are in the boat with us on this, it's primarily up to each of us to look after our own patch when it comes to spam protection, after all, it's not the ISPs' fault that you're getting it.
The AOL filtering caused all kinds of problems - I was sending email to clients via the BT smtp servers and seeing it bounced by the somewhat over-xealous AOL filter because it said the servers were being used by spammers. Other forum members reported the same problem.
Spam isn't the ISPs' responsibility, despite what some people might think - it's up to the entire IT industry (and governments) to find solutions. It will happen, but not for a long time, and until then we'll all have to do what we can. Incidentally, 70 spam messages a day isn't out of the ordinary, I was receiving at least twice that many on both of my primary email addresses at one point. My domain host has since introduced very effective filtering software (which I pay for), and I'm only getting about ten spam messages now. The magazine has also recently installed mail filtering on the mailserver, and my Forum editor address receives almost no spam now.
Mailwasher will do the same for you (FE winces, and dives under the table).