In the case of the 747 that would mean costly down time for the airlines to upgrade each and every plane in their fleets as well as having to make sure whatever the upgrade was is able to get FAA certified. It was just cheaper to leave it the way it was. Anytime something on a airplane get upgraded or modified it has to be very thoroughly vetted and approved by the FAA and that is a very long and very expensive process.

chrismeyer6 wrote on 2020-08-11, 02:21:

that is a very long and very expensive process.

And it's pointless to change a system that works. What's the gain? Some IT guy uploading the update faster? Not worth the extra.

How often do you replace your fridge? boiler, etc? they have gotten more efficient over the years as well?

As mentioned above, and everything in life it all comes down to cost/benefit and don't forget to include the rollout time, hassle of supporting 2 different systems during the migration, training and the R&D which would be massive for something as tightly controlled as a aircraft that would have to meet FAA (or in this case EASA being a UK registered plane)

On the flipside here is a well known system that's been proven to work, standardized across the fleet, and has all the required certification.

I wouldn't be surprised if the 787 uses a more modern system, but maybe not?