Consumer credits stimulate demand by increasing the cost consumers are willing to pay for a vehicle, shifting the demand curve, and greatly increasing the profitability in selling cars, provided it is done at scale. It can most definitely compell hundreds of billions of dollars of CapEx, and in many ways it's more effective than a tax break, because it will reduce losses if the venture never ends up being profitable (unlike a tax break which will only be worth it if the venture is eventually profitable, so there is less risk), and if it provides future market share through investments in the low end, especially in international competition, it can end up spurning more CapEx as it makes the more capital-intensive strategy more viable.