#3. From what I understand (I.E. take with a few grains or sacks of salt) systems like this are still new and not in full production, deployment, don't have all the problems worked out of them, etc. The Javelin and NLAW are already existing and proven weapons. Ukraine already had the means to train personnel and deploy them. "Hard kill" anti drone weapons do not have that wide spread use yet. The Russian use of waves of Iranian Shahed 136 on Ukrainian cities is the first time this has happened on such a large scale and it take both time and a need to develop countermeasures.
T here are a few systems using 40 mm grenade launchers or 30 mm automatic cannons with proximity rounds to destroy drones. Examples are the Striker SHORAD with Stingers and a long barreled 30 mm chain gun, possibly a laser weapon, and the Raytheon Pike which is a 40 mm grenade launcher fired missile. These systems are going to get a lot of interest for anti drone defense now.