I'm just curious when can I start buying my dream cars with altcoins, I mean can huge automobile companies like Toyota, Ford and Nissan start accepting cryptocurrency as means of exchange
Is your point is to buy a car using only crypto? Technically you can do it right now, you only have to exchange crypto for fiat money. Otherwise I'm afraid adoption level is not that high for official car dealers to accept BTC or altcoins. There is one possibility though - to find a secondary market dealer that accepts BTC.