Multi-verse is simply an effort to avoid the evidence, something like the epicycles in Ptolemy's cosmology. It is really about as scientific as astrology. People who are not religious, and I mean our secular educated, tend to believe in such faux science. Remember Nancy Reagan? Her kids are just like her, but the educated of all ages are as prone to superstition as their servants. Back in the 1850s, spiritualism in the big plantation house, (and in the White House); voodoo in the servant quarters.
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.