Comment by numpad0

Cost and complexity of certification? At least that was why Mitsubishi MRJ never went into production. They got the first prototype flying in 6 years, then sought to obtain certification for subsequent 9 years through various means before giving up and scrapping all ~10 examples. Kawasaki P-1 that flew in the overlapping timeframe is in production and in service, with IHI made indigenous engines albeit with teething issues, so it's not like planes and engines can't be made by anyone other than existing players. They just can't be sold, and therefore can't be* done.