A brief sampling of
US Missile "Defense" History:
June 24, 1997. First fly-by test of the Boeing/TRW exoatmospheric kill vehicle for the NMD system. A lawsuit filed by a former TRW employee alleges that TRW misled defense officials about the results of the test.
February 1998. First report issued by commission chaired by retired Air Force Gen. Larry Welch on the status of US missile defense programs. The report is critical of BMDO's efforts, finding a "rush to failure" schedule.
January 20, 1999. DoD requests more funds for NMD and announces the delay of the target date for achieving initial operating capability from 2003 to 2005, also moving the deployment decision date to June 2000.
September 1999. The Welch panel again concludes that the Pentagon's approach is extremely high-risk after assessing the reconfigured NMD program.
July 14, 2001. The fourth intercept test (IFT-6) of the ground-based midcourse system successfully intercepts a mock warhead. Later reports find that this test, like others before it, was aided by the use of a homing beacon in the mock warhead.
December 3, 2001. In this test (IFT-7) the kill vehicle successfully intercepted the target. One decoy balloon was used. This test was a repeat of IFT-6.
December 15, 2004. This intercept test (IFT-13C) of the ground-based midcourse system failed when the booster carrying the interceptor failed to leave the ground in a launch from Kwajalein atoll. The interceptor was to hit a target coming out of Kodiak, Alaska.
February 13, 2005. This intercept test (IFT-14) was a repeat of the test on December 15, 2004, and the interceptor again failed to leave the silo.
December 5, 2008. In this intercept test (FTG-5) of the ground-based midcourse system an interceptor launched from Vandenberg Air Force Base, Calif., intercepted a target launched from Ft. Greely, Alaska. While an intercept did occur, the countermeasures that were used (two balloons) failed to deploy. And even if they had, the decoys were reported by MDA to be "less sophisticated than the countermeasures flown in 2002," so the interceptor would have been less challenged than with decoys in tests six years prior to FTG-5. See the UCS report Missile Defense Test FTG-05.
January 31, 2010. In this intercept test (FTG-6) a target missile was successfully launched from the U.S. Army’s Reagan Test Site at Kwajalein Atoll in the Republic of the Marshall Islands. Approximately six minutes later, an interceptor was successfully launched from Vandenberg Air Force Base, Calif. Both the target missile and interceptor performed normally after launch. However, the Sea-Based X-band radar did not perform as expected and the interception failed.
September 2012. The National Academy of Science releases a report entitled “Making Sense of Missile Defense,” which called the GMD system “deficient” with respect to all of the study’s fundamental principles for a cost-effective missile defense, and recommended a complete overhaul of the interceptors, sensors, and concept of operations.
September 30, 2014. The Ground-based Midcourse System turns 10 years old. On September 30, 2004 the George W. Bush administration declared that the GMD system had achieved a limited deployment option (LDO) capability, meaning the system was now capable of being turned on and used if necessary. Only five interceptors were in place that day: it would be almost exactly two years before an intercept test of the kind of interceptors that were fielded was even attempted. It was another year beyond that—on September 28, 2007—before an intercept test was successful. On this date, the intercept test record is seven successful intercepts out of 16 attempts.
January 2016. MDA performs a non-intercept test of the GMD system, meant to validate fixes and updates to the kill vehicle and to gather information about how well the system can discriminate target from decoys. While described by MDA as a success, later information came out that suggested that one of the motors on the kill vehicle did not restart after being shut down, and that the kill vehicle veered far off course from its nominal target.
December 2016. Congress scraps the 1999 Missile Defense Act language and removes the modifier “limited” from the missile defense mandate, opening the door to building missile defenses intended to defend not only against the anticipated limited missile capabilities of North Korea and Iran, but those of the peer and near-peer forces of Russia and China. Congress also calls for the MDA to begin research and development, and to test and evaluate space-based missile defense programs.
March 25, 2019. Successful GMD test FTG-15 pitted two interceptors against a target. It was the first test of “salvo” engagement and the first operational, rather than developmental, test of the system. The GMD system has now successfully destroyed its target in ten of 19 attempts.
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Clearly not a great "success" record. But notice how the supposed "success" rate improves somewhat with time since the test ban, increased abstraction, and spending. The previous wisdom "If it ain't broke, don't fix it." -- meaning the test ban -- has now morphed into "It's broke, we gotta fix it!" -- meaning "Missile Defense" -- i.e. "Let's return to good old Cold War proliferation." Now why would the MIC want that? Gee, I dunno!

Perhaps they're insane?
Oh, I see I forgot to overstate the unspoken "obvious" again. Why test "live" missiles when you can get away with just "testing" dummies instead? Because "you" (meaning the Pentagon) get to control the narrative. "You" get to say things like "Success!" just because you designed and hit something you knew was coming and had long planned to hit in the first place. Buckshot's still relatively cheap, have you tried that yet? Would it really keep the actual thing from going KABOOM!?