But my real guess is that the warranty situation is simply the means to protect the established importer's territory. There used to be a thriving grey market with high-end audio gear from Japan. Bypass the dealer, and importer. But now, with the exception of perhaps phono cartridges, where they can't, manufacturers make sure locally sourced gear is specific to local electricity. It used to be that manufacturers built with multi voltage capability, and put a selector switch on the back. I don't think it's been that way for decades.
Yeah, the real reason is the usual anti-consumer BS, but it's at least more defensible with mains powered gear used at home. Even here, I don't think many people take their Accuphases on vacation with them...