Keyes was engineered by conservative Republicans in the state who are trying to take control of the party after our last Repub governor was indicted in the licenses for bribes scandal. I suspect they might be questioning that strategy right about now, unless they still believe Keyes can appeal to downstate, rural voters.
The main reason no “moderate” Republicans stepped up is that they see this as a losing battle. Obama has been well ahead in the poles, even with Ryan as an opponent. They’re looking forward and positioning themselves for a run for governor or other state-wide office next time – and don’t want a loss on their record. Keyes can sneak back to Maryland.
My hope is that Keyes will go down in flames and the moderates can keep control of the party and become viable again. (Same reason I hope Bush loses big – I can no longer vote Republican with the crowd now controlling the party.)