The Italian automaker would undoubtedly have benefited.
Volkswagen owns a lot of auto manufacturers, including Porsche, Bugatti, Bentley, and Audi, but it seems that the German automaker's appetite for world domination is insatiable. Recent comments made by Stellantis CEO Carlos Tavares have revealed that former Volkswagen boss Ferdinand Piech was very serious about buying Alfa Romeo. We can see how that would be beneficial for both parties, as Volkswagen would gain another iconic brand to manage and Alfa could have benefited from Volkswagen's leadership in much the same way that Audi, Lamborghini, and Porsche have. Remember, these all used to be embattled companies with contentious odds of long-term success before VW got involved.
Piech's admiration of Alfa was never a secret and he once publicly commented that the Italian marque would flourish under Volkswagen's ownership. He even had some ideas about how, saying back in 2011 that Alfa could be run by Porsche. Piech never saw this dream realized, but he never stopped wishing for it to come true. By 2018, Piech was no longer involved in the day-to-day running of VW, but he still had his dream. So when one of FCA's shareholders suggested that Alfa should be sold, Piech saw a path to his dream and prompted VW boss Herbert Diess to meet with Mike Manley, FCA's new helmsman at the time.
Reportedly, Diess "considered it his duty to follow through on Piech's request" and asked if Alfa was for sale. The answer was obviously no, but imagine how insanely brilliant a combination of the Alfa Romeo Giulia Quadrifoglio's handling and sound with Audi-level build quality would be. Although Alfa has declined to be bought in the past, the struggling automaker is a financial hemorrhage, and there's little hope for its survival. Perhaps Stellantis will sell the brand after all, and perhaps Volkswagen could be the lucky/unlucky buyer. We'll have to wait and see how this plays out, but it's unlikely that we'll see any big moves being made for a while yet.