The core issue with Boeing is that they have captured the government. Boeing the largest defense contractor, and one of the biggest lobbyists. Boeing recently successfully blocked Bombardier from competing with the 737 by getting the US government to effectively ban the C-series aircraft. (Bombariders "solution" was to give Airbus a controlling interest in a joint venture to build the C-series). I don't think this is really capitalism, it is corporatism - where the government and mega-corporations are indistinguishable and they only care about profits (and consequently about preventing competition)
It is the unavoidable end state of poorly regulated capitalism. When a player achieves regulatory capture, there is no amount of market that can fix the issue.
Exactly. They have capitalism in Europe too, where the Airbus is made, but they don't have these problems because they have much more effective regulation.