This goes missed a lot in debates about conscription. The Iran war in the US and the Ukraine war in Russia enjoy very little popular support among military aged men. This is in stark contrast to WW2, and even in Vietnam there was still a strain of thinking of draft resisters as cowards. But wars in this day and age enjoy a shockingly tiny public mandate, and it's entirely possible that governments can only do a draft on paper. Putin is practically unable to push further mobilisation because the first round provoked such stiff violence and resistance.