Actually most airports do have a surprising amount of snow clearance equipment. As I write this I can hear some in action.
Unfortunately the dead hand of Health & Safety and other regulations ("not qualified on this machine", "can't walk on snow without certified boots","hired-in plant stuck on the other side of security awaiting clearance", *proper de-icing fluid not compliant with new environmental rules", etc) means that it just takes so much longer to achieve the same thing as previously.