Selling 6 planes is nothing. It wouldn’t even cover the standby aircraft of many fleets. You need large orders to make it feasible, and you need a strong product to secure those orders. FedEx, UPS and co. aren’t going to fund you long term unless you have a product and you need good teams and good funding to even get you to that starting block.

Boom is probably the closest thing to what is suggested but many still doubt they will make it to production. That’s minimal investment though and mostly around options on orders, so they still need massive funding to get there. Rolls Royce and others have said it’s not viable to design an engine for them so now they have to design the airframe and the engine.

Bombardier is an example of why new entrants should be concerned. As soon as you become a close threat, you don’t really trigger competition you trigger massive protectionism which forces them to sell the design to airbus, further consolidating the market

I think the incumbents would have to be broken up to seed any new competition that is remotely viable. The Boeing story has some way to go yet though, who knows