For example, to make global validation work, given the distances covered and current technology (latency), a 10 min tact speed is optimal to secure the system. Or, the block size is optimal for current demand. Or the difficulty is currently optimal to main security and tact speed. Based on current computing power capabilities. That’s why the fear of quantum computing attacks is a non argument. Because it’s based in today, it’ll adjust etc etc; however, messing with the local optimum, like BCH, brings the system out of balance and sacrifices speed and security.