I've said for years now that two things will kill the classic (742). Turbines and trunnions. The engines are the most expensive part remaining on the ol' lady and the t-wheels are thier most critical part. The trunnions are only good for "x" number of overweight and/or hard landings before even Boeing engineering throws in the proverbial towel. As a former very high time FE on the girl, my mantra was always "if we aint on fire, we have time to dump". Purely economics,, twheels and trunnions.
On a positive side,, it really looks like someone is having a yard sale on -400 BCF's,, freakin' ramp is lousy with them.
--heracles