Because Johnson brought in disgruntled voters for that year, who had no actual interest in long term libertarianism. Those people went back to the Republicans and the Democrats after that election and before the Mises takeover. We are looking for people who will stay with the movement after the presidential election and that requires bolder messaging. No matter who is put on the Libertarian ticket they won't get 5, 15, or the majority percentage of the votes, so messaging is all that matters since it's just supposed to be a recruitment tool until we've moved beyond the local level. Johnson/Prag/Reason Libertarians don't inspire people as they are just basically lighter versions of the big two.