I was reading this article in The Edge talking about the days of these 2 monopolizing the markets may be over. It is interesting from the economic moat perspective.
How wide is the economic moat actually for them? In the case of aircraft manufacturing industry it is not the brand or the specific cost advantages. Rather their moat stems from High switching costs.
If you change your fleet of planes to another manufacturer out of these two you are going to acquire a full set of support equipment, services, man power. They may not be readily available. Technologies down to part levels coming from the same manufacturers may not changed much.
Most of all Safety is a high cost.
Changing to a China plane you have to evaluate all these hidden cost.
It still leaves me to wonder whether these small competitors can break their strangle hold.