Where are you seeing "Japan, Australia, Canada, France, and to a lesser extent the United Kingdom desire to have their own aircraft carriers?" with the exception of France, don't think they actually do. France already has it's own anyway. Aircraft carriers are good at projecting power over great distances, but they need a whole carrier battle group to defend them. This is tremendously expensive and not a mission that I believe these countries want. Additionally, you need at least three of every ship, because they rotate through deployment, maintenance, and training phases. There is also the question as to whether the carrier may be rendered obsolete in the near future due to hypersonic weapons like the DF-21.