There's no theological reason any miracle COULDN'T happen. God can work a miracle at any time, even if the NOM is invalid.
What's at issue is whether God WOULD work a miracle if 1) the NOM were invalid or 2) the NOM is as offensive to God and harmful to souls as we say it is.
I think we all agree that God would NOT work a Eucharistic miracle for an invalid Mass. That is in fact Bishop Williamson's argument. But I hold that God also would NOT work a Eucharistic miracle for a Rite of Mass that's not Catholic, offensive to God, and harmful to souls ... even IF it were valid.
Bottom line is that we're arguing speculations. BUT ... this does mean that Novus Ordo "Eucharistic miracles" are simply not theological proof of anything. Period. Satan can simulate miracles quite easily if permitted by God. If I were Satan, and I managed to pull off the NOM, one of the first things I'd be looking to do would be to persuade people that it's OK and valid ... by simulating some Eucharistic miracles.
"Cool. I pulled it off and replaced that abominable Catholic Mass with this invalid garbage. Now, some people are questioning its validity. Let me see. Hey, I know, let's fake a few Eucharistic miracles to put a stop to that."
See, this has always been the Church's attitude. We never alter Catholic theology based on purported miracles or private revelations. We use Catholic theology to test these alleged miracles and private revelations. If they fail the doctrinal smell test, or other tests, the Church declares them illegitimate. Then, if a natural explanation can't be found (including human fraud), the conclusion is that the activity was diabolical.
I know we've discussed this here before, but I'd like to refresh the topic. Let's suppose an absolute best-case scenario for the putative Eucharistic miracles, in Poland, Argentina, and possibly elsewhere. Say that unbiased, neutral DNA research is done on each of these miracles, and they disclose that all specimens, separated in space and time, come from the same person, a human male, and moreover, the haplotypes come from someone who would have been in Palestine and shared these haplotypes with Jews from that region. Or better yet, assuming this could be done, extrapolate that these haplotypes would have existed, in similar proportions, roughly 2000 years ago. Go one step further, and see that something about the DNA --- I don't know what that would be, but just for the sake of argument --- indicated there were no human father.
Then, go even
another step further, and assume that DNA analysis could be done on other such Species, such as the eucharistic miracle of Lanciano. Say it all lines up, and all gives us the same answer. What then?
I know one might protest "yes, Satan could engineer all of that". Two thoughts then: (a) we have made Satan almost as omnipotent, almost as omniscient, as Almighty God Himself. Indeed, a friend of mine in college (Jєωιѕн, BTW) said "you Christians make it almost as though there were two Gods, one good, one evil". Satan is neither omnipotent nor omniscient --- of a higher intelligence than any human, true, with angelic powers that no human has, true, but even with this conceded, he's not a god. (b) non-Catholic apologists of the Jack Chick variety (and those more cultured and erudite than Jack Chick was) could then come back and say "yes, and your older miracles, such as Lanciano, are of Satanic origin as well, ditto for Fatima, ditto for the liquefied blood of St Januarius, ditto for all your so-called 'miracles', and WRT your apparitions, Satan can indeed manifest as an 'angel of light' ". Then we're thrown back onto the argument of "if miracles buttress the contentions of traditional Catholics, then they're true, but if they bring one to other conclusions, then they're false". I hate to say it, but that's not the strongest argument in the world. Far from it.
I've had to wonder, then, if eucharistic miracles in the Novus Ordo can be seen this way --- yes, the Novus Ordo is valid, it confects the Body and Blood of Christ, and post-Vatican II priestly and episcopal orders are valid (because you have to have those for the Mass to be valid, unless you manage to get a pre-V2 priest to offer it), but that does not mean it was good to make those changes, and the Novus Ordo clearly has many, many other problems besides questions of validity. The whole traditionalist argument (or set of arguments) does not collapse like a cake when the oven door is slammed, or like a house of cards, if one accepts the validity of the NOM and post-V2 orders, and if those things are proved, that does not mean that we all have to run off to the Novus Ordo and abandon the TLM.