I am pretty sure that Boeing knows how to write a contract, getting a manufacturer to give you a date certain on delivery is practically impossible -- at least I have never seen it in my (albeit limited) experience. There could be an earthquake, or a strike, or an unexpected manufacturing glitch in any product delivery. Probably most of what liability they have is covered by insurance, unless insurance can claim that Boeing was doing this all knowingly or deliberately.
The grounded planes may be another matter, although I suppose that could be covered by the contract as well. It is not unheard of for planes to be grounded to fix technical problems, and the timeline for restart is not entirely up to Boeing. Even if there is a good case, unless they are backed by a nation state trying to cause trouble I don't see any airlines trying to force one of their two possible suppliers into bankruptcy; they would be bankrupt themselves (and everybody involved retired) before any possible payout was even contemplated.