Kendall is absolutely right.
"The targets that China is “worried about, that we present” are well addressed with hypersonic weapons" - US carriers and bases in Okinawa, Guam, and Diego Garcia + whatever means of power projection they have inside the rest of Japan and even South Korea.
"There was a “rush” during the Trump administration to develop hypersonics, Kendall noted, but they may not always be the most “cost-effective … tool” for the Air Force. “We don’t have the same targets that [China is] worried about,” he said. “We have to think about what’s most cost-effective for us … [Hypersonic systems are] very expensive compared to conventional weapons" Broadly, he said, the U.S. goal is “having a deterrence that defeats aggression, … whether it’s in Ukraine or … Taiwan, for example.” The “core mission” of adversaries such as China, however, is “to keep us out of their part of the world, or to keep us from intervening,” he said. These are “very different operational requirements.”
This is pretty much 100% candidly expressed truth. Differing objectives from differing adversary strengths respective objectives resulted in the forming of these very different strategies. HGVs are much less useful for the kind of military doctrine the US has pursued since the completion of the second world war and beginning of the cold war. F-14s with Phoenix against Tu-22 and supersonic anti ship missiles.
Chinese expertise and entrenched preference for ceramics made China ignore glass and glass making technologies for long enough to miss out on the microscope and telescope. The US being entrenched in carrier power projection and a new gunboat diplomacy (coupled with post ww2 geopolitics and American means of achieving hegemonic status) resulted in them ignoring weapons that are dedicated to A2AD for a long time. Compare them with the Soviets and all those supersonic anti ship missiles. The Americans just didn't have much use for those kinds of weapons. When they half assed tried hypersonics, they cancelled many programs and didn't see them through because they didn't have the same level of need.