It's apparently Ensemble's last project - not sure what that is all about.
Another reflection of the slowly dying PC gaming market, I think. Microsoft may have bottomless pockets, but Microsoft Game Studios still has budget numbers to meet, and it's hard to justify keeping a large development team -- with some very prestigious members, who therefore earn higher salaries -- on staff when it can generate only so much revenue.
Age of Empires 3 has sold more then 2 million copies
, that's great numbers. As far as I know that number doesn't include the expansion packs.
Honestly I don't know what's going on with MGS, they seem to be getting smaller and smaller budgets each year, or have decided to invest in timed third party exclusives instead of first/second party exclusives.