I see 3 potential outcomes for Steam keys if given to people that already purchased it. I redeemed the key and later purchased another Steam copy for a friend. I purchased One Hour One Life (smaller dev but similar structure of buy once, no server subscription) before it came to Steam and when they did adopt the platform I received a key for it. Xbox users would have no incentive for a Steam install and thus shouldn't receive a key.
If given a steam key, I would use it myself to migrate to the superior platform. I submit that steam is a superior platform, and I held out for months when the game was suggested to me by a friend because it wasn't on Steam.
I understand that Rare would be (rightfully) concerned that giving Steam keys to everyone that already owns the game a key would result in a flood of steam keys for sale and a resulting dip in sales. Need more details? Click here Helpful Links
Join the Sea of Thieves Community Discord The Pirate Code Sea of Thieves is an action-adventure free-roaming pirate video game developed by Rare and published by Microsoft Studios for Windows 10 and Xbox One.