You don't just wait, you prove that they all don't halt. There are only finitely many of them. You can't provide a general algorithm for proving that Turing machines don't halt, each one is going to require a special case - but it will be a fact that the physical instance of the machine halts or doesn't halt. (Or if it halts in some models of ZFC but not others, that would be even more interesting).
>>lmm+(OP)
There won't always be a proof. If there always was, you could programmatically find it via brute-force search and solve the halting problem.