Because they're built like a tank. Shimano started by making a scale model of a motorcycle brake, and everything since has had robustness compromised by the marketing department who saw that lighter and sleeker would sell and fragility was a problem people would tolerate.
May have had help from Nissin with manufacturing, Japanese industry works like that. The other rumour is that the designers may have seen the Grimeca System 8 before sitting down at the drawing board 🙂
Because they're built like a tank. Shimano started by making a scale model of a motorcycle brake, and everything since has had robustness compromised by the marketing department who saw that lighter and sleeker would sell and fragility was a problem people would tolerate.