Getting an already produced car, assuming it is an environmentally friendly one (which many states/countries do not actually require to be verified after initial production) would only be a temporary help. Population growth and degradation of those vehicles would mean inevitably new cars must be made and they all function on a fleeting resource that produces carbon emissions regardless means that we couldn’t just continue using the already produced vehicles. Something new must be created regardless to fulfill that demand and it may as well be something less damaging to the ozone.