Originally Posted by
procede
You would be surprised how much attention parked aircraft need, unless you accept you need to do a full A-check (or higher) before you can use them again. For one need to cover the engines and then uncover them when you start the engines every few days.
The 757 is dead. Compared to the 737 MAX9/10 it does not offer enough passenger or range advantage.
Revamping the 767 would make sense. High bypass engines, weight savings, aerodynamic improvements (sharklets) and integrate the 787/777 fly by wire system, so it is type rating compatible (and the larger diameter engines do not cause MAX like issues).
Boeing has published manuals and procedures covering how to take care of parked aircraft - not much need for day-to-day coverage by a large team of customer support engineers who normally deal with things like AOG and operational aircraft problems that the operator can't figure out how to fix.
I've long advocated for a "767X" - a new (or at least updated) wing, engines, and updated avionics - but my friends on the inside keep telling me that option isn't even on the table.
One of the biggest hurdles to any new mid-market aircraft is that currently there are no modern engines in the necessary 40k-50k lb. thrust range. So someone has to step up and commit to spending several billion dollars to develop a suitable engine.