It should affect buying decisions. What would a Tesla owner do if their car broke down and the company did not exist anymore? It's not like you can just go to an auto parts store or an ordinary mechanic.
It seems like used cars are significantly inflated in price these days - there don't seem to be many Daewoos left any more, but I just checked and people are selling 17 year old examples with 100K+ miles for $2-3K.