I am not sure how one can say for certain that "The laws of physics we know of can't explain this" ("this" being the apparently required low entropy of the big bang). In fact there is not yet any theory combining the "laws" of the standard model of elementary particle physics with those of quantum gravity, so we don't yet know whether or not such a combined theory will "explain" the condition of low initial entropy. If that low entropy condition really is necessary in order to explain the observed phenomena, then the real question will be whether or not it can be seen to follow logically from other assumed features of the theory (if and when such a theory is ever proposed and shown to be mathematically sound). If it does not, then noone will call putting it in a "deficiency" of the theory, but if it does then adding it as an extra assumption would be a deficiency of economy - and no amount of philosophizing can alter the fact that to determine which case applies will be an interesting mathematical question. Two issues that may be worth considering are whether the conditions for the combined theory (if and when one is eventually discovered) might require specially high symmetry (and so low entropy) at a point singularity, and whether any singularity that is not of low entropy could be associated with a direction of "time" with respect to which it qualifies as "initial".