Damned if they do and damned if they don't, Boeing want to get the aircraft back in the air asap however the fix has to be 100% because if there is another accident that's the end of the MAX. Boeing would then be left with several hundred unsellable aircraft which have cost them billions to produce and will be worth scrap value. They will lose their bread and butter income and have to survive on the B777/B787 and military contracts for several years whilst they need to fund the development of an all new replacement narrowbody which will be looked at sceptically by potential purchasers.
The British aircraft industry was dominant after WW2 until the Comet disasters, by the time the design flaws were sorted out the type had been overtaken by the B707 and British aviation never recovered. The Chinese C919 is only a couple of years away from first deliveries and might prove to be a credible option for airlines which are unable to secure Airbus A320s. If the C919 is a commercial success, Boeing will struggle to regain their position in the market and could be reduced to number three in the narrowbody arena behind Airbus and Comac. If the MAX is permanently grounded this would give a huge leg up to the Chinese aerospace industry and whilst the C919 currently falls short of current Airbus/Boeing types in terms of performance, once the orders and money start coming in improvements will soon follow.