Here's what I don't understand about DDoS mitigation. Say, they targeted x.x.x.x IP and it get RTBH'd, so the DDoS traffic is effectively stopped closer to its

Here's what I don't understand about DDoS mitigation. Say, they targeted x.x.x.x IP and it get RTBH'd, so the DDoS traffic is effectively stopped closer to its origins. Then, in order to bring my service back up, I move to another IP (or I adjust the load-balancing mechanism not to use the original IP). The part I don't understand is why wouldn't DDoS controller simply redirect its attack to another IP? This is surely not that hard to do, and so we are back to where we started and this cycle can in theory continue forever. Also, it follows from the above that the only way to dismantle DDoS attacks is to do traffic fingerprinting, detect malicious requests and then, ideally, have respective ISPs kick originating IPs off the Internet. Does anyone know which providers/services do this and how much it costs?