Yes, of course he can do that job. He'll be good at it. And more people will watch him and he'll make more money and such. So, yay Colbert.
But the job will be of a lesser nature than the one he has now which is probably the best thing currently on TV. That will be replaced with yet another clever guy who interviews celebrities with movies to plug every night. So.. net loss for the audience.
Oh.. but, apparently, it also means CBS has "declared war on the heartland of America" so that's kind of nice, actually.