Well Sandhi(and everyone who's interested)there are a few reasons why Goalkeeper will not be on the new frigates for the Dutch and Belgian navies.
here's an explanation by Sjef Pijls(who worked as a technical weapons officer in the Dutch Navy)
"Search for goalkeeper's successor in navy leads abroad in the first place"
DEN Helder
The Goalkeeper was a successful Dutch marine product. Now that a successor is being sought, a number of things have been determined in advance. The new weapon to protect warships from missiles or drones will not become a Dutch invention and will cost much more money than the Goalkeeper.
The Goalkeeper consists of a Gatling gun attached to a radar. The cannon raises a barrage of steel against incoming threats to the ship. "The new weapons should be capable of intercepting missiles, cruise missiles, grenades, mortars, drones and aircraft at very close range," said a Ministry of Defence spokesman. "They must also be able to retaliate very fast and complex attacks. They also need to disable fast-moving boats.
The House of Representatives is also working on the replacement. There is a lot of study, reports Secretary of State Barbara Visser to the people's parliament, but it will not be a laser weapon: "Defence is following developments in the field of lasers and is also conducting its own research into the applicability of laser weapons. For the time being, the technology has not yet come to the point where lasers can be used to defend against incoming missiles. However, the design of new ships takes these developments into account so that such weapons can be placed in the future", reports Visser. The U.S. Navy is one step further. Just before the summer, a successful test with a laser gun would have been done aboard a ship in the Pacific Fleet.
Cold War
"When I was on the material management in the 1990s, we expected Goalkeeper to be replaced around 2010," says Sjef Pijls, a longtime naval weapons officer. "This expectation was based on the then developments of offensive weapons, such as attack patterns, speed, misleading movements, the development of sufficient computing capacity, etc. Fortunately, by the end of the Cold War, these developments have not happened so quickly and I think Goalkeeper is still on his task. The system is now 35 years old and this means that conservation is becoming increasingly problematic and expensive."
The Royal Navy hopes to use it until 2030, while a successor is being sought to be introduced in the second half of this decade.
However, just as is the case with the worn cannons on the LC frigates, the age of Goalkeeper can cause a growing number of problems on board the war fleet.
Technical
Pijls mentions a number of factors: "The cannon has been out of production for twenty years and I suspect that spare parts become scarce; The technicians we used to have at the Navy company who could make everything may have been cut back by the managers. But electrical and electronic components are also unlikely to be delivered forever. At greater distances, you can damage the target's radar or shoot the wings off, on which it probably dives harmlessly into the water somewhere; that's what we call system kill. For this, the cannons and guided weapons are usable. However, at distances below 1500 metres this is no longer enough because the target is then in a ballistic orbit and there is a good chance that it will still hit the ship. At short distances it is therefore necessary to hit the combat charge with enough energy so that the target destroys itself, which is called 'warhead kill'. Goalkeeper has been developed for this purpose.
The problem with the replacement of Goalkeeper is that the weapon has to work from zero meters away and that can only be done with a cannon. Guided projectiles have a minimum distance on which they can function and although they are small in modern projectiles, it makes them unsuitable for the Goalkeeper role. The Rolling Airframe Missile, used by the Germans and the Americans, has a minimum distance of about 400 meters, but if it misses at that distance, even if it's only inches, it's really wrong. If Goalkeeper misses at 400 meters he can still take the target at a shorter distance.
Even though the extra-service commander has been an off-duty civilian for quite some time, Sjef Pijls continues to study on issues concerning ship cannons and ammunition: "We now have the same problem as in the 1970s: cannons with sufficient caliber have too low a fire pace and cannons with sufficient fire tempo have too small a caliber", the former officer outlines. "No doubt a new cannon can be developed, but for the relatively small need of the Royal Navy it becomes very costly. It must therefore be combined with other European countries; the policy of the Anglo-Saxon countries is mainly determined by the guided-arms industry (missiles, ed.)."
Caliber
According to Pijls, similar weapons systems, developed more or less simultaneously with Goalkeeper, both have too small a caliber: "The Americans have already moved away from Phalanx; I don't know why. The other weapon is the Spanish Meroka, which works according to the principle 'wall of steel' which has been improved each time and may work, but at too short a distance", according to Pijls. The Meroka works with two rows of six Oerlikon runs. It is an impressive cannon, but dates back to the eighties and is little younger than Goalkeeper.
On the arms market, there are plenty of modern candidates available for the so-called Close In Weapon System. However, there is a hefty price tag attached. Not only are the guns bigger; also the ammunition is more advanced and therefore costly. Grenades that fold open and throw hundreds of smaller projectiles into the path of the oncoming target produce impressive results. One example is the Oerlikon Ahead munitions that spread a cloud of metal, disintegrating a missile or drone.
There are more possibilities states Defense. For example, the Thales Pharos radar has been developed to disable air and sea targets in combination with a large caliber cannon. The Italian Leonardo-Finmeccanica also offers a new cannon, the Sovraponte. Thales, one of the most important partners of the Royal Navy, has developed an interesting weapons system for the French navy with Rapidfire. And then there are the Germans of Rheinmetall – also supplier of the Dutch armed forces – who have a close-in cannon in production.
Sjef Pijls is curious which system Goalkeeper will follow: "I have already been awake to this question and I assume that my successors on the management equipment are still awake from that."."
So as he said Goalkeeper was and is actually(after the upgrade)still a formideble system,and also interesting to read is that that a rocket/missile based anti-missile system isn't the best "end-phase"solution,it's still a canon based system.
It's a translated Dutch article.
Here's an old video when the GoalKeeper was demonstrated to the the US Navy.