It's inevitable that as economies grow in size and sophistication, that their engineering ambitions will grow also. In fact it's highly surprising that the Japanese haven't developed a civilian aviation manufacturer sooner - thy've excelled in almost every other engineering field.
It can only be a matter of time before China and India also become major players in the modern aviation industry, and I can foresee both countries offering competitors to Boeing and Airbus products within, say, 30 years. After that, Indonesia, Malaysia, South Korea, and many more. Russia could be back in the business after a few years of economic stability and growth, and Brazil is almost in a position now to offer large commercial aircraft to the world.
Boeing and Airbus should make hay while the sun shines on their empty playground!