Heavy ERA has some rather unpleasant side effects for any infantry in close proximity, plus it tends to make a royal mess of anything external (sensors, aerials) to the tank if it isn’t installed absolutely perfectly.
Think about it - you are blasting an array of metal out of the tank into the oncoming projectile. Like most explosives it will also chemically degrade with time, so older modules can be a bit…erm…unpredictable.
They are designed to protect the right vehicle, so what’s the problem? And modern combat has changed; you won’t see large mechanized columns anymore, they will be attacked by drones, nor by large concentrations of troops.
especially in urban environments tanks absolutely need an infantry screen, which is a problem when the tank is covered in heavy ERA that can kill its own infantry support if something hits it
The problem is the sodding great lumps of high-velocity metal that are flying out from a detonating ERA array. It doesn’t just vanish or go away once it has done it’s job.
Anything within a decent distance, supporting infantry (yes, infantry are needed to support tanks), soft-skin vehicles, even MT-LBs which are barely rated proof against small arms fire - is at tremendous risk of being cut to bits.
If anything, it is even worse in the drone age. Your nice ERA blast will probably sever any tethered drones on your vehicle and bugger up the EW/ECM gear on any vehicle that gets too close…
Now tell me how to protect the tank and the concentration of troops near it? Oh, you don’t know? What part of “war has changed” didn’t you understand? NO ONE knows how to effectively protect tanks against drones that can destroy their tracks with a small RPG charge, immobilize you, and then other drones come to finish the job, and you still want to put soldiers near the tank.
Erm…no. NERA is provided in the form of modules - pretty much like ERA blocks. Replacing them is no more difficult - if anything it’s easier.
True, not every ERA is as destructive. But anything like K5 and above very much is - simply due to the need to fire material out/down/up to disrupt an incoming dart.
Even then. The infantry is taught, at least in the US, to get far as F**k away from the vehicles, because they do their job and got you to where you need to go, and they haven’t stopped being a target since they drove you in.