> Zipping around in helicopters is over, once the opposition has anything that can shoot them down.

If that were true, foot soldiers would have been done once the enemy had anything to kill them. And the enemy had the ability to kill foot soldiers from the earliest days of warfare.

Everything in the battlefield in vulnerable. Everything.

Being vulnerable does not make something obsolete.

What makes something obsolete is when that thing is no longer the best way to accomplish any mission.