The plural of anecdote is not data. And GM sells a great many vehicles. Some are just fine. Some are "mechanically terrible". You'd have to look at big picture

The plural of anecdote is not data. And GM sells a great many vehicles. Some are just fine. Some are "mechanically terrible". You'd have to look at big picture stats to see how often it's the case. Most people that buy GM do not end up with mechanically terrible cars, but because so many are bought, a large number are. Beyond that, there are nationalists (will only buy American) or otherwise brand loyal, often taking up the same preferences as parents.