[glenstein]

Apologies in advance if I'm missing your point (I might be!) but... If it turns out that the laws are not constant, our present understanding would be retained as a special case of a broader theory and the local predictive capabilities would still be real in their scope. And leveraging a "we don't know" to cash out as affirmative skepticism tries to make the absence of data do more than it can.

As you noted, the degree of uncertainty we're currently wrestling with is also what we would see if it was true that the laws were constant. Kind of like an anthropic principle but on behalf of the constancy of the universe's laws.

This may all be restating what you said in a different way, but for me the important upshot is that I don't come out of it with an attitude that our current physical understanding is a tenuous house of cards and that I need to watch my step because, who knows, the strong nuclear force could change at any moment.