As Mr. Spock once said, "A difference which makes no difference is no difference."

I don't think Spock actually said that in the series per canon. He said that in James Blish's "Spock Must Die!" novel.

If you're versed in Cantor's Transfinite mathematics, subtracting infinity from infinity still leaves infinity. IOW, the Anti-Monitor could have wiped out an infinite number of universes and still left an infinite number over. Now, if we're talking different levels of infinity like Aleph-null, Aleph-1, etc. that's a different matter.

Berganza has said on his Ask Eddie forum that the mulitverse is bigger than we originally thought when asked about DC returning to a multiverse. This jibes with the above reasoning.