In general...
Tough to say. I’d say it’s fairly obvious that the NMA needs to become the NSA even with the Max returning to service early 2020. I don’t see a 767 NEO being realistic to bridge putting off the NMA. The 779X is starting to loose it’s desirability even if you disregard the GE9X issues. The 779X and A350-10 don’t seen to be filling in spots as carriers retire their 744’s. Boeing would be in better shape if the 778X were the first in the series IMO.
I see some good changes taking place in Boeing Leadership and chain of command especially with engineering. Muilenburg still needs to be removed if confidence is to return Lindblad leaving as head of the 737 program was a nice announcement last week.
It also depends how aggressive Airbus is during this period. They want Boeing to survive. The 321 XLR is a winner, but the 338 NEO and 350-10 have stalled. The 339 NEO is selling well now.
I‘d say let’s see where things are in 5-8 years. If the engineers can retake control of the product they will be fine. I don’t foresee China or Russia moving into these markets in the next decade. Russia can barely keep the grass on their taxiways trimmed, and the C919 is a joke.
Engine development will also be a large factor going forward. Technology is not maturing as fast as manufacturers claims. Precisely why we are seeing all the premature wear issues showing up on many of the NEO units.
Pressure to “Under Test” is the most dangerous trend in aviation today IMO.
Unless that stops everything else will be moot.