General Motors Co's (NYSE:GM) decision to invest $1 billion in Mexico is being pitched as a routine manufacturing expansion. But the timing suggests it's less about adding capacity — and more about solving a problem few are openly discussing.This isn't a demand story. It's a policy and positioning story.Track GM stock here.The Eligibility QuestionU.S. EV incentives aren't governed solely by where a vehicle is assembled. They hinge on a web of pricing thresholds, sourcing rules, and classification criteria — ...