There are two things being confused here. Cuba wouldn't have an auto industry if it wasn't communist, unless it adopted weird protectionist policies- no comparable countries do. Therefore, it relies on imported vehicles. Partly because of the embargo, supply of these is limited- particularly in the case of personal cars, the government had better things to spend limited hard currency reserves on while people could keep the 50s American cars from before the Revolution running (often with the motors replaced with smaller, more modern imported diesels).
However, that 'bus' seems to be a locally modified truck, probably a Soviet-built ZiL-164. There is definitely an argument to be made that the cars and trucks produced under Communism, both in the USSR itself and in client states like East Germany, Czechoslovakia and Poland, weren't as good as their contemporary Western equivalents for all sorts of reasons.