Whatever... however ya' want to dissect the technicalities.
The fact remains that hickory absorbs/dampens rebound (recoil) and vibration better than fiberglass or steel, which equates to less "energy transfer" into the handle and less "energy transfer" into the recoil, which means more "energy transfer" into/onto the object being struck.
The fact remains that a steel or fiberglass handle requires you to grip tighter and swing harder to accomplish the same amount of work.
The fact remains that a steel or fiberglass handle transmits a greater amount of shock and vibration to the hands and arms.
Why do you think steel and fiberglass handled hammers have a rubber or leather grip and all hickory handled hammers have bare handles???
The answer is simple... the rubber or leather is there to dampen recoil and vibration by allowing a greater grip purchase, something not needed with a hickory handle. In fact, if you watch someone who swings a hammer for a living they will hold a hickory handle loosely, some hold it so loose that they start the swing by holding it at about midway and allow it to slide out during the swing... if ya' tried that with a steel or fiberglass handled hammer it would bounce out of your hand and go sailing across the job site.
I'm not saying steel and fiberglass don't have certain advantages, but they also have major disadvantages...
Everything is a trade-off. If I was tearing a roof off of a building, where my hammer would be used more for pulling nails and prying up boards, I'd use a steel or fiberglass handle (likely steel). But when I started laying the shingles, where my hammer would mostly be driving nails, I'd switch to a hickory handle right quick.
I made my living swinging a hammer for a few years... and I've swung more than a few sledges, mauls, axes, hatchets and ball peen hammers... a hickory handle uses less energy and is easier on the body than any other handle material... hands down. I still remember the first time I tried using a a sledge with a fiberglass handle, bought a 16#er to bust the floor out of the garage at our family lake home... I made three swings with it, and I'm sure it's still laying out in the weeds where I threw it. I thought that thing was gonna' rattle the teeth clean out'a my head... went back to town and bought one with a hickory handle.
Nope, still disagree, there ya go with "feels" again. Subjective, non quantifiable without some reproducable standardized numbers to look at. How many test "feels" to a lb of head weight or whatever, and transferred momentum and so on. Let's see some numbers to prove your "feel" claims. Oh, BTW, there are numerous different types of synthetic handle material out there, they are not the same, so we'll have to get specific on exact brands and models and so on. and my anecdotal is the opposite of yours, on "feel". I prefer steel or synthetic. so, anecedotal versus anecdotal is a wash here.
With that said, there are numbers out there using testing machines, stanley, plumb, etc, with using actual testing machines and more modern designs, claim their multiple steel and composite hammers, for instance, are better overall than the pure wooden handled. They transfer more energy, with less felt shock, and are much more durable, the combination of factors they have to always look at. it can't be just one or the other, they have to look at all o the above. They look at the pros and cons and that's what they have come up with, for an overall better design. They build the dang things, and have plenty of engineers to throw at this subject, for decades. Their best efforts today you can buy are steel combined with composite, fiberglass or graphite, with specific antivibrational internal designs. Antivibe hammers. Those are their premium designs they make that makes them the premium bucks.
They are well aware of wood handles..wood is their bottom level tool handle material, if used at all, by the various manufacturers. Fiskars could use wood, I think they are aware of this "wood" stuff..yet they don't. I know some of the other guys do, and charge a lot..ain't seeing test results yet, nor used one, so can't comment there, but I am *doubtful* they out perform. I did like that baileys/fiskars test video though...
Not saying hickory (or some other woods) isn't a good handle material, it is, it most certainly can work plenty good enough, it just isn't top of the line anymore. That was then, this is now. Wood is inexpensive and easier to procure and machine, that's it for advantages. It doesn't transfer energy the best, it doesn't offer the most durability, it's not the lightest, and it doesn't reduce felt vibrations as well as the newer designs. That's the real "hands down". You have to look at all the various factors involved, because the tool works as a gestalt of the sub components and design. Wood is perfectly fine, no problems anyone wants to use wood, but real world engineering, proven by the various tool makers, shows that their evolved designs just work better overall, all factors taken into consideration.
if anyone--just talking generally now, addressed to no one in particlar, anyone "you" in other words, can prove otherwise, actually "prove" it, not hand waving on the internets and talking louder, but *prove* it, (you can get published after all in the various science and engineering rags..have to make it through peer review first so get your ducks in a row with your "feel" numbers), I bet those big companies making stuff like hammers would be willing to listen, and if you could change their minds with data, that wood is always better overall to use as a handle, and steel and fiberglass and graphite fiber are just a waste of time and offer no serious advantages, well, you could get *steenking freekin* rich. Companies love to cut expenses, they could lay off all their engineers and just use cheaper wood for all their handles all the time. Yep, you can still buy wood handled anything..that proves nothing other than products are made at various quality and price point levels, and people will sometimes actually pay some for nostalgia purposes as well.
I grew up as an archer. I was shooting a lot before I ever could ride a bicycle. I started with a straight (lemonwood) longbow. then went to a straight fiberglass..hmm, somewhat better. Noticeable. Then fiberglass and fiberglass/wood laminate recurves..hmm..better still..then a first generation fiberglass compound..flat shooting, nice.
Stopped there, ain't shot much since, decades ago, lost interest after one zillion arrows (which also evolved from pure wood -cedar) to aluminum and fiberglass (never owned graphite) but was an active competitor locally and did exhibition/trick shooting for some years running at the county fair, which as far as I went with that sport. The point is, the gear kept getting better as the smart guys threw skull sweat at it.
You just ain't seeing straight wooden bows, made by anyone, winning much competition..nope. They can still be plenty good enough, and beautiful, and feel good in the hands, and bring home the game, can be all hand made at home with just a little sweat and care and wood you harvest yourself, etc..but..they just don't perform the same as more modern designs combined with more modern materials.
I'm not gonna turn down a cheap used good quality wooden handled tool, snagged at a yard sale, etc., of any kind, definitely worth picking up a decent old widget for two bucks, whatever, but I am not going to be paying full price on any new ones unless they have full modern materials and design science incorporated into the ..whatever I am buying.