I'm sorry, but I simply don't see a direct connection between how you choose to finance your company and how you plan your engineering strategy. Boeing made a decision to modify the 737 instead of building a new plane. But that's a perfectly valid strategy. Hell, Boeing's chief rival is Airbus and their equivalent of the 737 Max is the A320 neo- they did exactly the same thing. It's a fine strategy. The problem was that Boeing was trying to cut costs - which is a natural and expected part of a large company. The problem was they executed that badly and the company culture became bad. But that really has nothing to do with the debt structure of the company.
this is what happens when top management is compensated based on stock value and the bottom line.
Instead of doing their job, top management practiced shares buy-backs as a way to increase share price.
I think we'll get a new motto soon - if it's Boeing, I'm not going...