What I like about Indonesia is that they actually try to build their commercial aircraft industry and their state-backed company is not afraid of investing in the project. Korea is on the other hand has discussed developing a turboprop commercial aircraft over two decades without any result. I believe one point KAI considered partnering up with Indonesia. Now KAI considers to build a Dash 8/Q400 series under the license with an option of buying the entire production line for Asian market. The problems with Korea, Japan and China have been the fact that they try to build a commercial aircraft with 70~100+ seats straight way. They may learn a thing or two from Indonesian commercial aircraft programs.
That's too much of a stretch, by far.
First off, If they aren't doing it that way, there is obviously a reason for it. The regional jet market is a highly saturated, dominated by very few manufacturers. See Embraer selling their stakes to Boeing and Bombardier withdrawing from the market they have dominated for a long time with CRJ series and a turboprop that is now DHC Dash 8. They've stated that the development cost is too high for them to continue the C series program and the return is constantly diminishing.
You might say that the situation is different in the market for even smaller sub-10,000 Kg MTOW class of aircraft but that's wrong. Casa and Cessna were always in this market and the C212 is doing just fine. Now Cessna as shown in the other post is entering their new aircraft as well and I don't see anyone in the commercial market outside of its country of origin favoring a new commercial aircraft from any of those Asian countries against proven CASA material.
On the other hand, China is brute forcing anyways with all their state-backing and huge domestic market. Their two short-haul jets are no where near its Airbus or Boeing competitors, but from development stand-points its doing just fine. They will be able to break through someday, and it would have been waste of time if they were to develop a plane of the size of N219 or C-212 only to wait for it and then proceed with C919 or ARJ21. They have a long history of building planes anyways, so it was rather wise to go straight into regional and short-haul jets market. It's rather just a choice for them to either develop the 7000 Kg MTOW class turboprop aircraft or not.
Japan has already developed YS-11 a while ago and has built it for quite some time. Apart from that, they have other experiences of developing a subsonic multi-jet aircraft like P-1, so once more its rather just a choice if they go for a bigger commercial aircraft or the smaller one.
Considering the fact that, when Mitsubishi started the MRJ project the tourism and aviation industry were growing rapidly and the factor that led all these growth were LCC flying regional routes, it was just plain obvious (no pun intended) they would be missing out when they were to do what you are suggesting.
Of course the MRJ has been delayed so much that they even changed its name but its rather just hindsight. Also, even if they went with the sub-10,000 Kg class short-range turboprop aircraft, as I've mentioned above, the competitors are just too strong.
Most importantly, you find way more domestic demands within Japan for an aircraft sized that of MRJ than C212. Thus its a private company doing private project. Yes, there were some government support but in the end Mitsubishi pursuing a bigger market is a no brainer.
Last but not least, Korea and KAI's plan of developing regional turboprop aircraft has been stranded for an obvious reason. On top of all the problems I've mentioned above, the most important problem is that there ain't no domestic market within Korea to justify the development of an aircraft of this kind.
Indonesia is spread across so many archipelagos and several huge islands. Even if they have a hard time selling their N219 internationally, which they probably would given the strong competition from way more established aircraft manufacturers abroad, they still have their domestic market.
Korea is the direct opposite. Half the Koreans live within the 50 Km radius from Seoul, the rest live in cities with either decent or to be accurate, overkill airports on which even mid-haul aircraft could take off and land or train stations where KTX runs through. With KTX you could get from one end to another within 3 hours and that time is only getting shorter with the new generation of KTX about to get introduced very soon.
There is just no place for turboprops in Korea. Even the few Dash 8s that were operated in Korea were replaced in favor of C series and 737. It would be plain dumb for KAI to develop an aircraft like N219.
On top of all these its not like making a commercial aircraft is vital for national security. Now that industry giants like Boeing and Airbus starting to poke into regional jet market, thus new players like COMAC joining the game, its also unlikely that even more new and smaller players like KAI could make a profit long-term. No, its gonna be a miracle if they somehow manage to break even. Its gonna end up like a pile of mess that is MRJ and withdraw from the market like Bombardier. There will be no one to take the responsibilities of tax-payer money being dumped into the pit.
I'm very glad that Korea was able to avoid that path.
