I don't think the ISP's problem (opportunity) resides in the scenario you're describing. The problem is the top .0001% of Internet destinations congest the ISP generic network interconnects. Hence, these larger vendors (Netflix, Akamai, Cloudflare, Amazon, Google, Apple, etc) either pay the ISP for direct network peering or server hosting to sustain acceptable performance. However, this typically leaves the cost of growing internal network backbone capacity on the ISP. I believe the scenario you are describing would allow ISPs to offset this capital cost to both the big content providers and the biggest consumers.
> Which is solved by discriminating between services how?
The point about torrents and bitcoin is that these applications are particularly burdensome on routers because of the amount of connection requests as compared to a fairly manageable HTTP or RTSP session. As I mentioned above, server co-location and direct network peering is already a thing that many larger ISPs offer on a non-discriminatory basis. However, most new businesses will piggyback on existing cloud hosting (AWS/Google/Azure) or CDN (Akamai/Google/Cloudfront) arrangements.