Not this again.
Look, why is this so hard to understand?
The military is trained to deal with enemies who surrender when confronted with overwhelming firepower.
'
Shooting at walkers, shelling walkers, and bombing walkers, simply attracts more walkers from miles around.
Do you think that their supply of ammo is unlimited or something?
Do you understand the concept of finite resources?
They do not have unlimited supplies of ammo.
As ammo runs out, they must be re-supplied. This can't happen if factories that produce the ammo are shut down because they are being overrun and the people needed to work them are fleeing. But that's just one of hundreds of possible complications that would lead to the military's rapid demise.
Not to mention supply lines getting cut off for more reasons that you can possibly imagine.
Ammo isn't the only one thing that the military needs. Fuel for vehicles and aircraft are needed. Where do you think that comes from? It has to be transported from point A to point B, like everything else. Transporting them requires people who, once again, are bailing and/ or being killed by the unleaded.
The military would likely secure the parameter around the city- which accomplishes nothing, because new walkers are being spawned inside the city itself, people are dying not just from bites but from any number of causes.
Yeah, some military might have been bailing to go be with their families.
My guess is that most of them simply ran out of bullets and were killed by hordes of walkers.
Simply put, the military are limited in terms of manpower and they need supplies.
No army in the world can defeat an enemy with unlimited manpower who doesn't require food, ammo, and supplies. .