Conservatism is much more than that. Leftists have in some instances learned that they are utterly dependent on conservatives to pay the bills and hold society together as they, the leftists try their repetitive and foolish idealistic experiments. Without conservatives, the socialists rapidly turn into Zimbabwe.
No socialist system can exist, even for a short while, unless there is somebody outside of the system paying for it. An excellent example of this was Sweden, whose socialist economic system was totally supported by their huge, capitalist armaments manufacturers-exporters, that were outside the system, yet paid huge taxes.
Yet despite all, socialism was a huge drain on this industry, always demanding more and more resources, yet providing less and less to the people in the system.
Finally the socialist PM, Olof Palme, decided to kill the goose that laid the golden egg, by nationalizing the arms industry, so that all its profits could be used to feed the socialist monster. So there is a strong suggestion that the arms industry recruited an insane man to assassinate him.
Once he was out of the way, cooler heads prevailed, and began a systematic deconstruction of the most expensive and irrational parts of the socialist programme. Thus Sweden slowly began to recover.
So for all the contempt and hatred the left, communists, anarchists, neo-Nazis, socialists, liberals, eco-nuts, etc. have for conservatism, they are utterly dependent on it, and its efficiency, productivity, solidity, and literal militancy, or progressivism would die out entirely.