What actually gets published tends to be filtered by its political content. In particular, results with a liberal bias tend to be promoted.
[1] In classical economics, the reverse holds. It's very hard to show that any mechanism is possible under the assumptions of classical economics. Hence the huge number of negative results: (a) Coase theorem, (b) the Modigliani-Miller Theorem (irrelevance of capital structure) and (c) Ricardian equivalence. All these results basically say that if you try to do X (where X is (a) change people's actions that have externalities by assigning property rights, (b) change the value of a firm by changing its capital structure, and (c) change people's actions by government spending), the free market will completely undo your actions and leave the situation unchanged.