The issue with zombie firms is not really furlough itself but the fact that anything that prolongs a zombie firm's life will mean that firm is still sucking up

The issue with zombie firms is not really furlough itself but the fact that anything that prolongs a zombie firm's life will mean that firm is still sucking up things like credit and capital that would inhibit the ability of new firms to take their place. And firms that are clearly dying take a long time to finally die; even in the US, where firms are not really supported, department stores like Sears and Macy's limped on for a decade or two. The extreme version of the sclerotic economy is probably Japan, with an honorable mention for Italy. Policymakers desperately want to avoid falling into a zombie trap, because there hasn't been a country that has made it out of one yet.