69-110 billion, 90% of the people who've ever lived are dead. That's a lot of folks to be resurrected. Take away we who are Apostates (a million or two) that still leave 67-110 billion.
Raining down manna from heaven will not cut the mustard for 100 billion people, there is not much you can do with manna, manna bread, manna tacos, manna soup and manna sweet cakes.
There is not enough resources to to house and feed 100 billion people, 7-8 billion today.
I'am not a economist or mathematician but the resurrection will create a whole set of new problems for mankind.
It becomes a bigger problem when you figure in those folks the lived before Adam that the Bible forgot to mention.