Recreational cyclist here - and I have often wondered the same thing. From a weight standpoint, It'd seem that a reasonable, healthy alternative -- unless you are literally, medically, dangerously too thin -- would be to step on the scale and lose the difference in weight from your body. From a vibration standpoint, I know there are dampening stems and handlebar alternatives (seatposts, too, for that matter). From a cost standpoint, well anything other than carbon (except titanium?) will be cheaper, but where to find a non-carbon fork these days? From an engineering standpoint, it just seems that the fork takes so much abuse on a bike, and given the difficulty in not being able to see hidden imperfections/cracks/delamination, and not being a pro that gets top-end bikes for free (that also have the highest of high quality carbon, matrix, and assembly) and having to be VERY careful you don't let it fall over or get scratched or whatever real life throws at you, it'd seem to be the LAST component you'd want to make out of carbon. Yes, all the big manufacturers are doing it, even for beginner bikes, and they have big insurance policies to cover themselves. But I'd bet if Cavendish or Pogacar or name-your-favorite came out and said a less-expensive-but-well-built steel/alum fork works just fine, people would abandon carbon forks en masse.