It's really because regardless of his other flaws, Paul is the lone small-government conservative in the race. The huge number of GOP primary voters who still care about that are giving him a long look whether they want to or not. The danger for the GOP is that if the majority of these voters decide Paul's other views are too far out, many of them will simply stay home.
I guess you see Paul is back on the Alex Jones show today. This is not good.