They don’t realize they don’t have big ideas. In fact, they believe that Medicare for All will fix stuff even as most Medicare recipients use a “gap” insurance plan, that impeaching #45 to install a theocrat in his place will fix stuff, that we can continue this Global War on Terror without causing enormous harm, destabilizing the world and emboldening authoritarians across the planet, that the Russians are the reason there is not a Democrat in the White House. There is a whole essay on these fantasies which energize so many on the left.