I wouldn't say it doesn't matter. Opportunity cost, loan amount vs gap insurance, etc still matters.It happens in the stock market every day. The difference is it won't matter, even to those who bought cheaper. Because they'll all depreciate to nothing in time.
Problem is you can't return a car after you bought it, and if you can wait it is probably easier to cancel order before delivery if there's a rumor they are about to drop price (by checking the trend in used car price drop amount).