The way to lower the price of used cars is to subsidize new cars and then waiting 3-10 years. But that doesn't work well either, because pricing is global, and because the demand split for EV/ICE changes every year.
These feel like scaling down costs rather than trickle down economics. Almost every home good or vehicle, electronic devices, computer parts were super expensive when they came out. The initial presumably rich people fund the factories that eventually mass produced them by buying these super expensive goods which lowered the prices to where the middle class can afford them. It also allows companies to iron out initial issues with production and usability before mass producing items.
Government subsidies and incentives drive this process faster and make it more likely to not die out by trying to ensure that the companies can survive when upfront costs are very high before the first few goods can even ship to the few people that can afford them. Trickle down economics is something quite different.
Back to reality: such effects smell like trickle down economics to me. They may work, provided the rules stay the same. Around here, the govt eradicated the subsidies on hybrids right before the first generation lease hybrids were about to enter 2nd hand market. So we collectively sponsored a bunch of well-off consultants getting fancy cars that were, after the leases ended, all exported :s.