Comac will make better and better aircraft. It won't stop Airbus or Boeing being viable companies any more than it will stop Bombardier, or Embraer. All airlines make political compromises. Wings are assembled inside one economy, so the aircraft can be sold inside that economy. Or, engines are maintained inside that economy. Or, a new JV is spun up which blends both economies interests somehow.

If you look under the covers, Bombardier has had many acquisitions, sell-offs, "manufactured under licence" in it's time. Not bad for a snomobile company!

Aircraft are not bought solely on price, despite what people might say about fleet bidding. operating costs might be a stronger reason than initial fleet acquisition cost. Or cost of compliance. Or pilot re-training. or, in the post MAX crash era, reputation.

(not in the industry, don't drive an aircraft for a living)