Being a Keyes fan myself I hate to say this, but there is a perfectly good reason they gave Donahue a longer shot.
Keyes was basically plunked into a losing timeslot as a fill in for them. They had no great expecations for the show. They just wanted more of that "right wing talk" stuff that was doing so well for Fox.
Donahue was the basis of an entire new strategy meant to make them competitive in primetime with CNN and Fox. They shuffled all their existing shows around and created new ones around their Donahue centerpiece. They poured huge marketing dollars into promoting the show. No doubt there are many careers at MSNBC other than Donhue's on the line if (and when) his show fails.
No doubt there are many careers at MSNBC other than Donhue's on the line if (and when) his show fails.