a couple of things spring to mind
first new Alfas are often bought by the people who buy them for how they look, and do not understand the importance of the above
then the dealers make matters worse by either not coughing up for warranty work or not fixing it at all
and looking at one website there are quite alot of old Alfas still going which may pull the average down a bit, BMWs and Audis do not last any better, they just go out of vogue in business circles and get scrapped after 10 years as technology is old and any prestige has gone, an Alfa on the other hand still looks pretty and drives well. and contribute to such surveys skewing the data.