There's more than one reason bodybuilders don't use insulin with long half lives. I don't think you know much about insulin
Pretty much every body builder who uses insulin uses Lantus for coverage, and aspart or even R for large carb meals or large carb intake periods around training.
The use case of insulin is to keep your blood sugar in range when intaking large amounts of carbohydrates and/or using HGH which can chronically elevate your blood sugar levels. It also acts as a nutrient partitioner. It is a storage hormone for managing blood glucose. Not some sort of magic muscle drug like amateur bodybuilders on forums once touted it to be.
But sure, please tell me what I don't know about a drug I use every day to manage my blood glucose.