The problem with "strategic ambiguity" is that it is a work of realpolitik from the 1970s. The ambiguity was required because at the time Washington recognised the ROC itself as a potentially destabilising and disruptive actor. If Taipei were confident of America's support, they might be emboldened to declare independence which would sink the whole enterprise, i.e. Washington's attempt to re-engage with China under the PRC.
The problem in sustaining this is two-fold. First, it is simply discordant with generations of rhetoric and instinct on Washington's part. Public figures in Washington cannot now conceive of Taipei as a source of problems because of course a democratic society that wishes to be independent should be supported in that objective. Democracy is good, self-determination is good, America is good, therefore Washington must support Taiwan. These are the same ideological convictions that led Washington to support Kyiv in the path that led to war, rather than unilaterally make, and encourage Kyiv to make, concessions that may have averted it. Realists are much more comfortable talking about power and interests, but I think it is a mistake to ignore the ideological, indeed mythological aspects of these things. American rhetoric is not only a mask for the pursuit of American interests, to a considerable extent these people actually believe what they say.
The deeper, structural problem, one that realists would indeed recognise, is that Washington is increasingly uninterested in sustaining "strategic ambiguity" because it is increasingly uninterested in sustaining a relationship with the PRC. If you have come to view the PRC as an existential threat to be opposed on every front, "strategic ambiguity" starts to look less like a deft piece of realpolitik and more like craven submission to the enemy. And so Washington is walking away from "strategic ambiguity" and openly encouraging pro-independence sentiments in Taiwan. As with Ukraine and Moscow, most figures in Washington would say and believe that they do not actually want war. But they are not particularly interested in avoiding it either.
