No Infanteer, I am not confusing co-ordination levels.
On the other hand co-ordination is at the heart of this discussion.
The environment is target rich in ballistic missiles, guided missiles, autonomous missiles, Micro-Mini-Maxi UAVs, vertical take of and land and fixed wing, single use and recoverable - and I haven't mentioned traditional threats like Helos and Fast Movers.
BG45s GBAD battery is going to be deployed 8 km forward of the High Value Asset that he is defending. I hope for his sake that there is an infantry battalion between him and the ATGM gunner targeting him. And that they can do their job rather than having to hunker down under their SKOP kits waiting for the skies to clear.
I get that life is messy but the issue is one of managing to accomplish mission in spite of alligators rather than waiting for the swamp to drain.
I don't consider it an acceptable response to say that you lot in the front line should not have an effective means of protecting yourself against threats directed your way. Space is zero. Time available is comparable. Waiting for someone to prioritize the immediate threat to your mission, your men, your machines and yourself does not, on its face, appear to me to be an effective course of action. There aren't enough Infanteers as it is. Let alone allowing the available numbers to be attrited by smart, cheap munitions.
The reaction time needs to be reduced - and apparently the technology exists to reduce the reaction time to 0.5 milliseconds. Can you squeeze the PTT button in that length of time? Let alone form a complete sentence, have it acknowledged, discussed, prioritized and a decision taken as to whether to spend the money to protect you, and allow you, your machines and your men to carry on with the mission, or hold on in case the Brigade CP is actually threatened by a Fast Mover - some day.
See, I actually think that a sky clear of fast movers is infinitely more likely than a sky clear of 40mm grenades on autopilot.
At the coal face those decisions, that process of getting inside the enemy's OODA loop, demand localized decision making ability and also demand localized response capabilities.
We'll start at the start...
1. Yes, obviously if a GBAD element was deployed in front of the defended asset (8 km was the example) in the case of a BSA, DSA, airfield, etc than there would be a force protection element there. That's why "normally" GBAD is deployed TACON to infantry bns... they coordinate local defence and the Bn commander can, if he or she chooses, put assets in the larger bubble. That said, the detachments will defend themselves (hence the "AT" on the end of ADATS... the AT function was designed to improve survivability not as an actual secondary capability).
2. Priorities are based on threat, criticality, vulnerability, and recuperability. The threat is key as the primary objective of GBAD is to defend against non-fast movers but to provide a "back-stop" to the fast movers (countering jets of all varieties are the primary function of the Air Force and these can be engaged relatively far out in a positive IADS as airfields will be identified in the Air IPB process. The reason infantry tend to be lower on the priority list is because they tend to score lower in vulnerability and higher in recuperability, in that infantry can hide from a threat easier than a field battery and are more replaceable than guns, CPs, MLRS, etc.
3. You seem to be focussed on the fast mover aspect of this discussion, which to be honest, isn't the foreseeable priority. UAS, munitions, and aviation are the largest threats to the field force. UAS of all natures are the primary threat, imho, with munitions being next and aviation being the most dangerous.
4. It's the localized decision making that is the basic problem of giving untrained infantry units MANPADs. Unless they have the integration into the IADS, the training to identify friend or foe, and the ability to establish an effective AD protection area, than it wouldn't be effective and would likely endanger friendly aircraft (The RCAF doesn't even like the idea of qualified AD Sgts conducting engagements let alone a sort of qualified infantry Cpl). Further, how would IFF work for a UAS threat? How could someone in a trench line with no radar tell if a small or mini UAS was friend or foe? in your example, they would need to hop on a radio and ask the Bde HQ or would need to be tracking all of the ASCMs associated with their area. Your solution would actually greatly increase the time needed, not reduce it.
5. I agree with infanteer that you are confusing active defence of an AFV with air defence.