Gabe Newell in an interview to IGN said that "
Hitting Steam Deck Price Was 'Painful' but 'Critical'". That means they
might be eating some of the costs to release their PC/console at 399, but at the same time, it's completely open and people can even install other stores on it.
Something seems wrong. If they're investing in a long term plan to increase the adoption of Steam, why would they make their platform open and allow people to replace the OS and install their competitor's stores?
Just for some context, in article Gabe also says “We’re doing this for the long haul. And there’s a lot of opportunity.”, so this is clearly a long term plan and they've been working on this for a long time.
What do you think is their master plan?