It's the reduction in manpower equation where the problem comes in. Unless you jump to a Terminator world where every weapon system is autonomous, then the math will always be (T x P = E) where T = technology; P= personnel and E = effect. In short where where there is a doubling in T then the formula becomes 2T x P = 2E. But if you simultaneously reduce P by 50% then it becomes 2T x 0.5P = E. In other words the advantage that the increase in tech has produced is reduced by the reduction in manpower resulting in effect being unchanged. The aim is always to increase E through an increase in T. You do not want to settle on status quo. On top of that every increase in T has its own demands. While there may be less P required at the gun, more are required at other points along the chain.
Let me give you a simple example. If you replace a dug-in M777 with a 10 man crew with an RCH 155 with a crew of 2 then the illusion is that you have a five-fold reduction in manpower - but you don't. The RCH works differently. It flits around from hide to hide to shooting positions. At each hide you need an ammo resupply crew, local defence, CUAV etc. All things that your ten man crew would have accomplished. That alone will eat up over half of your imagined personnel savings. On top of that, with its small on board ammo supply, the RCH is "out of action" more than the M777 and unable to immediately respond to calls for fire (and I wouldn't trust its fire on the move function as much as the glossy brochures state) - it needs to take the time to deploy. Then there is 24/7 operations. Your two man crew and some of your ammo folks need to rest or rotate which again takes your gun out of action for some of the time unless there is a replacement crew available. The result is a slower response to calls for fire and increased time out of action to rearm and rest means you need backup teams/stand-by systems.
The trick with all of these systems is that you have to closely evaluate how the changes in T can be used to maximize E. That rarely happens by simultaneously reducing P. Just as important, changes in T also occur on the enemy's side. You need to be immediately ready to compensate for the enemy's increase in E against you which usually requires more T and P on your side to provide countermeasures and to replace casualties.
I really have no problem with the numerous introductions to technological changes that you bring to the forum. I generally welcome the information. My problem is with the conclusion that we can instantly reduce the number of people needed in a given function or move them to another function based on only a very small part of all the factors involved with introducing such a system.