"Conservative" economics have never failed, they have always performed as designed, society is just not included in the success.
In general, conservatives believe that conservative policies can not fail, they can only be failed. By definition. That is, the policy is the goal itself, as opposed to a good outcome from the policy being the goal, as it is with liberals. If a conservative policy leads to a bad result, as they usually do, it simply means the policy wasn't implemented with enough fervor, and the bad people didn't have enough faith in it.
Thus, when trickle down fails ... it means we need more trickle down!