Ain't gonna happen and it isn't at all that easy:
UBIsoft and Oleg already have an agreement and it even couldn't be canceled, when it was decided that the next games will be released by Atari.
As much as I understand your wish, it ain't gonna happen for SoW.
It also makes little sense to distribute it by Steam or similar means only. You should be aware that there are much more people playing this game offline than online, some by consideration, other because they simply don't have internet access. They'd lose all those customers by pure online-distribution!
Let's not forget that the US is the only nation that has a law to grant all citizens access to the internet.
