Who is going to have over 100m? Nobody, max is 99. Who is going to be able to afford things at 1.0 prices? Nobody, because we're all having our gil reduced. Who is going to undercut to the new POST-CHANGE VALUE of items? Lots of people, which will even things out. But whatever, have fun thinking the gil redenonimation matters at all (aside from some inevitable early inflation).
Have you ever seen The Incredibles? It's a great movie, with an awesome quote ..something along the lines of "Saying everyone is special is just another way of saying nobody is". .. Well in this case its "Everyone is losing something, so nobody is".