I don't see how the PSR fails based on your terminal chain. Doesnt the LCA also work in reverse?When something terminates - when its existence comes to an end - isnt that equally explained by Leibnitz?The same God who is given as the explanation for a thing's existence is also offered as the ultimate explanation for why anything does not exist - because if God wanted it to exist, it would.
I think your objection misses the essence of Stephen T. Davis' reformulation of the argument from contingency (this is the version that Craig defends).Everything that exists has an explanation of its existence, either in the necessity of its own nature or in an external cause.Premise (1) clearly has to do with things, not facts. It is completely consistent with there being brute facts about the world. Perhaps the causal series of contingent entities terminates with a necessary being, and that necessary being freely wills the existence of contingent things. Likely, the fact describing the will of the necessary being is simply brute, and the argument, as Davis formulates it, is unaffected. In short, we still come to a theistic conclusion even if we do not affirm a strong formulation of Leibniz's principle of sufficient reason.