I like your idea of a prestige studio, but I think the reason prestige brands exist in consumer goods is because even the company needs a mental separation between 'them' and 'us'. Audi has to be separate from VW, Acura from Honda, otherwise the high margin/low volume brands and the penny pinchers get confused by each other an fuck everything up.

So it couldn't just be called Valve or Blizzard, it'd have to be called something else.

If they do it right though, some interesting things could come from it. VW's high end is always full of parts that started life on an Audi and they learned to make more cheaply over time.