I think old(er) age happened.
There is still a backpack - but a suitcase transferred by local taxi as well. When we started doing this type of long national trail walk years ago most people carried all their stuff in a pack. But in recent years I would say that 80%+ use luggage transfers for cases and just carry the day pack.
Changing times! All pre-booked and the transfers account for about 10-15% of the cost with the rest mostly on accommodation.