Sacks’ claim was conditional and medium‑ to long‑term: if cheap drones/missiles kept being used against U.S./allied ships while the U.S. remained stuck using very expensive interceptors and lacked a cheaper counter, then over the coming years the cost asymmetry would “really change the balance of power.”

What has happened so far (through late 2025):

• Houthi and other Iran‑backed forces have continued using relatively cheap drones and missiles to harass commercial shipping and U.S./allied naval assets in the Red Sea, forcing sustained air and missile defense operations by U.S. carrier strike groups and destroyers. Naval News’ detailed account of early Red Sea operations describes U.S. destroyers and carrier air wings expending large numbers of missiles and other munitions to defend against Houthi drones and anti‑ship ballistic missiles, validating the basic cost‑exchange problem Sacks described. (navalnews.com)
• Senior U.S. Navy leadership has publicly warned that the current heavy reliance on high‑end interceptors like SM‑3 and SM‑6 against such low‑cost threats is financially and logistically unsustainable in more intense or prolonged fights, again underscoring the cost asymmetry Sacks worried about. (businessinsider.com)
• Analysts estimate that defending against Houthi attacks has cost the U.S. several billion dollars, while the economic damage from the attacks themselves and the cost of the Houthis’ own munitions remain far lower, explicitly noting that "the cost‑exchange ratio of the campaign favors the Houthis" even though the conventional military balance still overwhelmingly favors the United States. (realclearworld.com)

However, the stronger claim that this cost asymmetry has already “really change[d] the balance of power” in favor of actors like the Houthis is not borne out:

• Expert assessments continue to emphasize that despite the favorable cost‑exchange ratio for the Houthis, the conventional military balance and broader regional balance of power still strongly favor the U.S. and its allies. The Houthis have become a serious asymmetric nuisance that can impose costs and disrupt shipping, but not a peer force capable of overturning U.S. naval dominance. (realclearworld.com)
• At the same time, the condition that “we don’t have a good response” is beginning to erode. The U.S. Navy has fielded and tested directed‑energy systems such as the HELIOS laser on USS Preble as a low‑cost counter to drones and potentially some missiles; only one destroyer is currently equipped, but it shows movement toward exactly the kind of cheaper defensive layer Sacks said was missing. (en.wikipedia.org)
• Other states are also investing heavily in similar low‑cost air and drone defenses (e.g., the U.K.’s DragonFire naval laser contract, Israel’s Iron Beam, and U.S. high‑power microwave systems like Epirus Leonidas), indicating a broader push to close the cost gap rather than passively accepting a permanent asymmetric advantage for cheap‑drone users. (reuters.com)

Netting this out: Sacks’ intermediate observation—that the Houthis are exploiting a dangerous cost asymmetry and that the U.S. has been using very expensive interceptors against cheap threats—has been validated. But his full prediction was about a substantial, longer‑term shift in the overall balance of power “over the coming years” if nothing changed. As of December 2025, the U.S. and allies still retain clear military superiority, and significant efforts are underway to develop cheaper counters. The time horizon he invoked has not fully elapsed, and the drastic balance‑of‑power shift he warned about has not clearly occurred.

Given that, the fairest assessment today is that the prediction’s ultimate outcome is still unresolved, so it is inconclusive (too early) rather than clearly right or wrong.