Well Bitcoin mining could "break SHA-256 and render it insecure" by: 1. exploiting cryptanalytic weaknesses in SHA-256, 2. successes in new computing paradigm

Well Bitcoin mining could "break SHA-256 and render it insecure" by: 1. exploiting cryptanalytic weaknesses in SHA-256, 2. successes in new computing paradigms such as a large scale quantum computer using Grover's algorithm. 3. or turning the local galactic cluster into computronium for SHA-256 miners. Although at that point we have bigger problems. =) If you think SHA-256 will not be broken anytime soon then that suggests that you believe that mining difficulty increases will slow down.