Free market, it will open up a lot of opportunities for new companies
As I understand it, the only peer companies that do so are Airbus, COMAC, and Embraer (Edit: Bombardier ended with the A220).
Which one of these should replace Boeing?
https://www.reuters.com/business/aerospace-defense/brazilian...
Four planes.
However, Northrop Grumman could also buy out Boeing's large aircraft bits and (re)enter the commercial airliner market.
I doubt Lockheed Martin would be interested, they're into smaller aircraft these days.