so, basically a country around WW1 level tech came to this world, and stagnated because they were so much further ahead of everyone and didn't have other countries scientists to bounce discoveries off of. And now meeting a country that lived through an exponential tech growth age. Which leads to the idea that Japan will probably stagnate while in this world after a few years of tech left in the research pipe exhausts itself, plus some slow improvements here and there.
Unless they attempt to bring other nations into the same tech & education level, and then it would still be several generations before any kind of tech race begins again.