The criticism that Boeing is not much more than a company putting the pieces from all over the World together at their final assembly lines is not dreamed up out of the blue sky, but a real and objective transcription of todays situation, especially delicate considering that the final assembly is a solid , but not a huge part of the value chain of an aircraft. The development is based on public funding anyway...

Wing box and wings are certainly major competence centres handled by the Japanese, however the learning curve within the industry is so huge that you need to invest ( and lose ) billions before having an aircraft on the market.

Considering that you need to have a family of aircraft nowadays to survive and the cashflow of a new development, the respective Government of Japan or China must fund such projects big big time before they are a serious competitor, however especially China seems to be willing to do so...