I had a few wooden handled traditional axes in the past, and through time, uses and weather changes the wooden handle either shrinks or expands making it either loose head or split in the wood. On few occasions the heads came off while swinging as well, which were not safe and also resulted in loss of work and time. Trying to fix these problems were much hassle and waste of time. The Fiskars have given me no problems in that sort. The edge going a wee bit dull and chipped is not real problem in wood processing unless axes being used for shredding papers. But we have scissors for that.
I can sure see your point and in recent years lots of people in the north have come to depend on a Fiskars which actually works dependably. Steve Acker had gone up into the mountains to run some tests on his vintage axe heads which he had recently re-handled and the results were poor due to the seasoning of the handles he had been able to acquire. On one axe the handle split and on the other axe the head loosened.
Up until about ten years ago I had no problems collecting wooden handles from industrial supply and farm stores, which after a year of being stored at home dried sufficiently to prevent those issues. I'd go through stock in the spring when new shipments came in and buy a bunch, so finishing the drying at home was important in avoiding any further issues with head loosening etc.. In the past few years, costs have been cut by not seasoning wood for the years required and so a person first has to find a decent handle, then store it for years... That's not too practical for most people, but the handle will be dependable after that..
Years ago I bought a Hults hatchet to try out against vintage stuff. All the Agdor stickers just mean that it has a handle made by the famous Agdor handle works, not some third world outfit. I was incredulous when I weighted the hatchet, subtracted the weight of the head, and found just how heavy that short handle was. I replaced the handle, but kept the original filed the varnish off the ends and weighed it every few months. I'm still amazed by the weight loss, because I wonder how all that water could actually have been present in such a small handle. Weight loss was many ounces.
I've had luck with Gransfors handles, but basically these days unless a person is willing to pay a premium or be very patient while their new handle seasons before fitting it, then they are likely going to experience just what you have.