time-ex - if you look into it, you'll see that JAL123 was not repaired properly, and failed almost exactly where predicted when they worked out the mistake had been made in hindsight.
still, the fix for the 787 looks far from straightforward - the damage area for the structure will be extensive - far more that what is visible and could well be very complex, and could be a write off.
more worryingly, if the ELT just ignited with no obvious manufacturing defect, then we could be looking at another rather costly AD.
still, on the bright side, the ELT was probably almost brand new, which may mean that there is a hopefully an obvious issue to find.
it is only speculation that the ELT is to blame - too early to assume that I think.