That’s because his viability is all in your head. No data supports it.
Keep dreaming.
You mean data like the highest favorabilty rating of all GOP candidates? The highest "conservative" rating of all GOP candidates? The fact that he is, by far and away, the most common "second choice" for those voters not already voting for him?
On top of that, his favorability rating in Iowa is about 10 points higher than it is nationally, again, clearly 1st among the entire GOP field. Add in to that that some 50% of Iowa caucus voters say they are either undecided or are still open to changing their minds (cross-reference to the "second choice" stat above), and I'd say there's plenty of data to suggest that Thompson is not only "viable", but that he could dramatically exceed expectations.