“and therefore Eliyahu, a bas kol, or any other form of heavenly intervention should be able to resolve the issue.”
R’ Mattisyahu Salomon shlit”a spoke today about this exact topic. He said that s/o approached the Bais Haleivi and asked him since there is convincing and conclusive proof that the true tcheiles has been identified why should we not wear it. He answered that there are 2 types of mesores – 1 is in halachah. If a halachah has become forgotten/discontinued, and s/o can prove or establish the veracity of a halachah then we would continue it even though there was a lapse. 2 is in metzius. If there is a break in the chain of metzius it intrinsically lacks the mesores even if it’s authenticity can be established beyond the shadow of a doubt. This is because once there is a lapse, there is by definition no longer a mesorah-it has to be an unbroken chain directly to Moshe Rabbeinu. However, should Eliyahu Hanavi z”l identiofy techeiles for us, that would reestablish the mesorah, since he would be reconnecting the link to Moshe rabbainu. This line of reasoning would apply only to Eliyau Hanavi and not to a bas kol or any other form of heavenly intervention as this would not constitute a continuation of the mesorah of Moshe Rabbeinu but rather it would be considered an independent source. Incidentally, This inability to continue with tcheilus is the biggest testimony to the strength of mesorah. It is precisely because Korach va’aduso challenged tcheiles in such a public forum, that the message of the strength of mesorah is delivered through our inabilty to wear techeiles due to its lack of mesorah. Conversely any mitzvah we have today, sukkah, lulav etc. is backed by the strength of our mesorah I hope I understood R’ Mattisyahu correctly.