In the era of virtual servers, cloud infrastructure, CDNs, etc., ASNs and IP blocks are not necessarily that helpful. Which is kind of back to my original point: it's not 2005 anymore.
Maybe you'll get to the same destination but I very much doubt it. Of course, if your starting goal was to snoop on the customers and you were just looking for an excuse...
The above statement makes no sense at all. The whole Internet is built on connections between autonomous systems and all traffic is IP based. There is nothing but ASNs and IPs and information about them and the flows between them is extremely helpful in operating an ISP.
I also don't disagree about the usefulness of this kind of information, my argument is that ISPs can't always get by on coarsely aggregated data alone.