I think you may misunderstand the problem. We assume internet traffic is compromised and we take steps to reasonably secure that traffic.
Even if your ISP has a compromised router, the only thing the baddies would see is your outgoing and incoming traffic. In other words, they would only see internet traffic. Egress and Ingress traffic can be secured with the use of IPSec VPN or similar technology. As long as anything sensitive is transmitted securely, a compromised ISP router isn't much of a threat.
On the other hand, if your router is compromised, the baddies can see LAN side traffic and that's a whole other can of worms.