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 $500 that means you invested your money for a year to get it doubled and be able to buy a car with it.
The cheapest Mercedes-Benz costs way less than 34 475$. Also, they do not accept Bitcoin, so anytime you bought them, you could not have bought a car with it. Mercedes bought a Bitcoin payment company, but this does not mean that they accept Bitcoin. This was just a pure misinformating thread, probably to give some more logs to the fire, which is people buying bitcoins. By doing this, OP hopped that the price would go faster because, now, Bitcoin would get accepted by major companies, and the average Joe would have filled its sell orders.