Your basing that on one car which done well the brand and rest of the models done very badly. Parkers which is a sister company of fleet news explain it better.
Anyway if anyone has a spare 10 minutes go online and check brand reliability tests and see how bad BMW scores. You will be as shocked as I was.
Also Kezo the which score is based on a public survey rather than way you described it as in their own tests like they do on white goods.