I'm just wondering if they are having problems choosing their priorities: their home consoles or their new cloud-based platforms. No matter how it's spun, they eat into each other's markets and in house resources.
I think MS has made it clear that GamePass/xCloud is where they see their future. With Scarlett, I think they are just seeing if it is financially beneficial to release more HW, not worrying about units sold, but profit. This is why I doubt MS is going to be subsidizing the cost of Scarlett. At most, I think they will try to break even, maybe take a small loss, covered by the sale of a single game. It might be a case of figuring out what they can throw in there to match Sony, without having to sell it for more than $499.
On the other hand, with the way Sony is talking, I wouldn't be surprised to see them subsidize the price by $100-$200.