You know this for a fact? :-)
I'd agree that the idea of 'multi-verses' is not necessarily probable. That doesn't mean it isn't true, of course, but it's just a theory. As far as I'm aware, no one claims it to be absolute truth . . .
And of course people are still easily fooled. And since education does indeed help people be less easily fooled, then the people of the past were more easily fooled.
But the real irony is that your argument works against you. Since people are so easily fooled today, that is even more evidence that we can't just take it as gospel (pun intended) that the Jesus story was true.
As you point out, some people can believe anything. So the belief of the apostles doesn't prove truth.
The right comparison with testimony in a court. Which witness do you believe? Which side better explains the facts of the case. But you assume that a jury constituted today, selected at random, is better qualified to decide the matter than one likewise constituted two thousand years ago. If we are trying to decide a narrow point of law, where all the advantage of experience matters, or where the witnesses speak a certain language or are under a certain legal code, then and only then one set of jurors will be superior.