Very interesting post and you might be right I am really not sure.

If not by mass media, what else could achieve this?

God can in an eyewink put up a "big screen" for all to see, like he put the son and the moon in the sky and everyone can see it. Like He will come back to earth and the Bible says: every eye will see Him.

But I don't say that you are wrong, I am just saying God will find a means if it is predicted in His word. If it is by "mass media" so be it. Is there other sources sharing this opinion of yours?