in theory (mathematically) it's more productive (in operating businesses that can put the capital to good use quickly), but in practice, that's not necessarily true. markets are not perfectly efficient, and have hidden losses as well (e.g., productive asssets being sidelined due to competition). governments are capable of putting capital to good use (hoover dam --> california expansion, at the expense of the environment, a hidden cost).

neither markets nor governments are perfect, and such superficial arguments are at best misleading. you can't just compare idealized markets to practicing governments to reach substantive understanding.