I took the opposite message from the article. It describes how difficult it is to concentrate enough resources to successfully attack a hardened defended position, when the defenders can see you coming and destroy you from afar one piece at a time.

Locating the fixed, hardened positions of the defense is relatively easy. Locating the mobile assets of the offense and destroying them before they attack is the new thing.

Scouts and cavalry have had this role this for ages, but drones plus guided munitions are extra good at it.