I didn't hear if the Mercedes-Benz accepting bitcoin and tesla is never making an announcement about they were officially accepting bitcoin for their payment. Especially for apple too. 
I wonder who has that amount of bitcoins to buy a Mercedes? I think that this statement is more PR the shares of these companies. Besides if anyone can buy a car with bitcoin then it will be free to talk all the news in the world.i just googled "Mercedes-Benz price" and their prices actually start from $34,475 and it is ~34.4 bitcoins right now and you could have bought that much with a lot less last year. even if you bought it at $500 that means you invested your money for a year to get it doubled and be able to buy a car with it.