Why would they? that just waste of money.
People may mock their Forza Halo Gears only and that's understandable(for people mocking them playing too safe), but at least these 3 series keep making money for them, meanwhile timed exclusives pretty much tells you helped nothing, if we look back for the timed exclusives they signed.
Because they don't have the studios to make exclusive games, so they buy them from third party. And a timed exclusives is more likely to happen. Just look at Tomb Raider or Dead Rising...
Also just look at this hilarious tweet from spencer
https://twitter.com/XboxP3/status/811350267991969792
He said this but then he buys ROTR, dead rising 4, exclusive stuff for the division etc... I'm starting to think he's just a fake person that try to act like the good guy...
He's actually not doing anything good for the xbox brand.