well, airbus and boeing have a lot more money and r&d available, which makes it harder for new entrant. Even someone with a lot of experience like bombardier in producing CRJ series is having a real rough go at it with C-series. Once Airbus saw a possible challenge, they came out with NEO series by using a new engine and sharklets and some changes and voila, C-series gets crushed. It's much easier to get into the regional airliner market where embraer is at. There is a reason why all the new entrants try to compete in that crowded 70 to 90 seat segments rather than trying to get to 135 to 200 seat segment.
That is not true, the reason why Airbus and Boeing make more A-320 and B737 than B47s and A-380s is related to the Market, most people will fly shorter routes.
Learjet 85 was cancelled because the price per seat of this type of aircraft is high, it means a ERJ-145 will be sold in larger numbers than a Phenom, why? a Phenom is a smaller jet thus it means fewer people can afford to pay the price of operation of a Phenom than of a ERJ-145.
Bombardier can not compete with Airbus simply because they do not have the aerospace background Europe has.
Airbus is backed by well established companies that were making from Fokker 70s, Comets, and Caravelles, in few words they already have the market, experience and costumers for their jets.
Airbus was not a new company in terms of experience, the companies that merged were already making concord, Comets, Fokker 70s etc etc.
Bombardier did not start as an aircraft company, but it started making snowmobiles, so in order to gain customers they started with turboprop aircraft which require less fuel (jet engines consume more fuel) thus the price of each seat is lower than in a jet.
Embraer was the same, their first aircraft were turboprops, small ones.
To exemplify if you open a business you have to make profits, all business start small and if profits grow they become larger.
Embraer said they were not going to make a larger aircraft, because the market was over crowed, with the MRJ, MS-21, C919, C-series plus the A-320 and B-737, you have several countries trying to fill the same niche, some of these companies will fail.
Plus probably you do not know Embraer has connections with US and European aerospace industry that make parts for both Boeing and Airbus as well as for Embraer, so you do not know that basically the same companies that make money with a A-320 make money with a ERJ-145.
So Embraer will keep making E-170s because companies like Daher or Aernova or Goodrich or Honeywell make aircraft parts for Airbus, Boeing, Embraer or Bombardier, so in few words the reason why Russia and China and even Japan will have a hard time selling their jets is based upon the fact the western companies are themselves owned by the same people . and they share the spoils regardless they have offices in Sao Paulo, Otawa, Washington, London or Madrid,