Simply because they didn't bid on that contract. The bidders were SpaceX, Dynetics and the Blue Origin-led "National Team" (BO, Lockheed Martin, Northrop Grumman and Draper).
Boeing also bid on the original contract, but was kicked out of the competition at an earlier stage. Their bid was rejected because it didn't address key requirements in the contract solicitation.
A senior NASA manager, Doug Loverro, is accused of reaching out to Boeing and trying to help them amend their bid to avoid it being rejected. For a NASA staff member to offer help to one of the bidders is illegal, and due to that, Loverro was forced to resign from NASA, and is now under criminal investigation. He justified his actions on the belief that without Boeing in the lander procurement, the lander was dead. I guess today's announcement just proves how wrong he was.
A senior NASA manager, Doug Loverro, is accused of reaching out to Boeing and trying to help them amend their bid to avoid it being rejected. For a NASA staff member to offer help to one of the bidders is illegal, and due to that, Loverro was forced to resign from NASA, and is now under criminal investigation. He justified his actions on the belief that without Boeing in the lander procurement, the lander was dead. I guess today's announcement just proves how wrong he was.