> Essentially, I'm operating a system, and if you can
> guarantee the system functions as documented -- I
> don't really care how the sausage gets made.
The thing about the incentive, though, is that a software fix ticks the "we did something" box, as long as it improves the issue to any degree. That it does any good at all, combined with the lower cost, can give management (or ass-covering employees) enough substance to rationalize the decision away.
I doubt anyone at Boeing would willingly risk customer lives. But if they are working under pressure, and can say "well, we did do something to address the issue," that can lead to bad decisions.