Point 2: Decentralized consensus on how to proceed takes time. The chain will halt and need to be snapshotted in a temper resistent way. Courses on centralized hubs will crash. Mining hardware will become useless forever and miners immediately lose their source of income. Different people will lobby for solutions that fit to their capabilities. Modifying code in chaotic and stressful circumstances may lead to bugs that get exploited later without being noticed long enough so that snapshots will not be an option.