Bayonets weren't intended to be sharpened. I sharpened one of mine for utility reasons but leaving the rest as are.
I've heard a couple different reasons why -- 1) that non sharpened bayonets create more ragged wounds that are harder to repair (tearing rather than cutting), 2) that non-sharpened bayonets are less likely to cut into bone and become stuck, 3) that military powers as be didn't want soldiers using their bayonets as general purpose knives and by using them accordingly damaging/misplacing them, and 4) that bayonets made of soft metal were less likely to snap than hard metal but the soft metal didn't get/hold a good edge for regular use.
More modern bayonet/fighting knife combos that are sharpened seem to come about after the recognition that modern infantrymen are unlikely to use their knives as bayonets, but still keep the bayonet lug on the knives as a just in case thing to avoid negative publicity/CYA for generals/politicians in the event of logistic/supply failure -- the troops run out of ammo... And the justifiable concern of both soldiers and leadership with overall combat load weight (prob moreso soldiers than leadership), it makes sense to only require that soldiers carry one bladed weapon.
That said, I don't think that the US Army even teaches use of bayonets these days. Believe it's just now "combatives" predominantly hand to hand focused.
However, I question the "curio" logic though -- British forces have executed two bayonet charges that I'm aware of in both Iraq and Afghanistan (unlike the US more of their troops seem to be more thoroughly trained in light infantry tactics including "outdated" tactics like bayonet fighting (and they have shorter bullpups!):
Helmand Province Afghanistan, 2011 or 2012:
www.gov.uk/government/news/bayonet-charge-foils-enemy-ambushBasra Iraq, 2004:
liveleak.com/view?i=0bd_1249524865If you're curious about the British vs US light infantry tactics, you should check out Max Velocity's books. He served as both a British Paratrooper and Army Ranger; born British and now a US citizen and discusses in some detail. Dont' recall the specifics offhand. He has a blog and website as well.
Further in regards to "curio" infantry tactics -- I think the base assumption of vehicle mounted and engagement of enemy hostiles primarily by stand-off support forces focus of current US infantry tactics is a mistake... I'll save the tangent other than save very few US soldiers are taught more than the basics of classic infantry maneuver and that vulnerability/assumption of always having technology/air/sea/tank/artillery support and/or superiority for our troops will eventually lead to the US' own Dien Bien Phu (20k French/Friendly Indig forces killed/captured by 65k Chinese/Viet Minh troops) be it in current conflicts on forthcoming ones (suppose one could argue that the Battle of Kamdesh in Afghanistan was essentially a modern day Dien Bien Phu just on a smaller scale -- just like Operation Redwing or Battle of Shok Valley as modern day "Black Hawk Downs" or the Second Battle of Fallujah as a modern day Battle of Hue City). Regardless, tactically I think military leadership is failing our troops just like the have (IMO) w/ the M4 carbine, the Army UCP camo, the F35 boondoggle, the attempted A10 scrap, etc... Or at a minimum that lack of proper tactics training will lead to more US casualties when the full force of America's battlefield dominance/technology cannot be immediately brought to bear against enemy aggressors...
