Neither of those things could help Japan. Ultimately old people are going to need nurses and other people to provide services for them. If there are not enough young people willing to do those jobs, then all the money in the world is useless.
Nothing stopping them from importing nurses from abroad when and if they get to that desperate stage.
The parent, parent, parent comment (by victorhooi) is stating that Japan's problems stem from its reluctance both to have children and to allow immigration. Your answer -- that they should change their attitude toward immigration -- doesn't refute him or me, it agrees with us.