They’re defunct as living arts, but we know enough to know that they were extremely sophisticated - wrt to Western MA, from the mediaeval/renaissance fight books, and wrt Eastern MA from still-twitching remnants like the koryu in Japan, and family/clan martial arts systems in China, India, etc.
I also think history demonstrates that fighting styles will adapt quickly to available weapons so to a certain degree the weapon manufacturers can just do their best within simple categories like “light as possible while still acceptably strong/sharp.”
How should it taper? At what point along the blade to taper? What curvature, if any,and what type of curve? Should the cross-section be an I-beam (wide runnel) or a wedge (with a smaller runnel)? What kind of hilt?
Or do you think manufacturers just randomly made weapons of various shapes and sizes, and people had to adapt or die? ;)
I also think that going on about fighting styles sort of misses the point. A serious weapon doesn’t get a fancy art developed around it. Fancy arts are for aristocrats with too much free time.
I don’t think so. In a time when people killed each other with cutlery, and killing people that way was the main way to kill people, people practiced a lot, even commoners. The idea of clueless, skilless idiots being conscripted doesn’t match the reality of what one glimpses in the fight books - and even earlier, going right back to the ancient Greek city states; or looking to the East, the way the civil service system in China included military lore, and military training of locals was part of the responsibility of civil servants, particularly the aristocratic ones.
To take an example I’m familiar a bit with the detail of. What’s generally known as Tai Chi, or Taijiquan, is a martial art that originally comes from a village called Chenjiagou in Henan, and was originally the property of the Chen family/clan that lives there. For several centuries, the clan was locally famous for producing bodyguards for merchant caravans, and contributing heavily to bandit defence in the locality. This was a simple farming village. People did all the hard farm work, but still found time to train - and still do.
Now, originally, the “hand form” (the slow training movement form generally known as Tai Chi) was part of foundational training to be able to use weapons with an extremely unusual set of body skills. And there are a few weapons forms in Taijiquan. However, there doesn’t seem to be much paired practice or combative training for their use left (unlike the koryu in Japan). But at one time, the whole point of the hand form training would be to lead up to being able to use weapons skillfully. This general kind of scenario is repeated through a lot of the obscure Chinese MA - they are localized remnants of what were once things people living in villages used to stay alive.
No, as I understand history and from what I’ve read, when melee was common, people of all walks of life trained as much as their interest and spare time would allow. Because if your chances, as an adult male, of being conscripted or dragged into some form of melee combat or battle was quite high, as it was in all times and places prior to the 19th/20th century, there was a high ROI in even a bit of training.
Obviously, the more free time you had, the more time you had to hone those sorts of skills, and that would favour aristocrats to some extent. But that can be exaggerated. Being an artistocrat during most times in history in most cultures has had duties as well as privileges. So some level of skill was common to most males. Even the equivalent of “sport” fighting was common for youth in many cultures - kids learning basic wrestling styles, etc., as a foundation for more military forms of combat (in Chenjiagou, as in many villages in China, kids commonly learn Shuai Jiao, kind of like generic Chinese wrestling, in the same way that in the early to mid 20th century, many British kids would know a bit of wrestling or boxing - but those kids who learn Taijiquan go on to learn a different from of Shuai Jiao that’s incorporated into Taiji).
A serious weapon has be mass deployed to infantry and learned quickly. Infantry need a basic drill they can master in a few months of training tops. For the last few centuries prior to rifles making all melee obsolete, the sharp metal weapon of choice for infantry was the bayonet. That’s not a complex weapon with subtle metals. It just needs to be reasonably strong and pointy for thrusting.
The bayonet isn’t used in a context where melee is the main form of combat, it’s a fallback, a vestige. (I can’t remember where, but I recently heard a comment from a soldier who served in Vietnam talking about how soldiers often used rifles as clubs in melee, as much as they used the bayonets :) )
Again, while of course it did sometimes happen that militia would be untrained, or unskilled relative to aristocrats or professional soldiers, or had to be trained from scratch, I think it was probably quite rare - in fact, usually when you see that, it’s in the context of a lament that they’re not better prepared, with the implicit expectation that they ought to have been (as in “this country’s going to pot, wasn’t like that in my grandfather’s day”, etc.).
Think of it like keyboard skills today. Because people have to type and text, they either gradually learn to hunt and peck fast, or they invest a little bit of time to learn how to type properly; of those who learn to type properly, some go on to be extremely fast and accurate. But most people know how to use a keyboard; some level of keyboard skill is pretty much ubiquitous in our society. That’s because that skillset is necessary to learn in order to survive/thrive in our society.
It isn’t necessary to learn how to use melee weapons in our society, in order to survive or thrive. But it once was - and in parts of Asia, the time when it once was is much more recent.
Another way to look at it is: why did guns become popular? The main reason is that, relative to the level of proficiency in melee weaponry needed to kill efficiently on demand, training for proficiency in firing a gun well enough to kill efficiently on demand, is much easier and quicker. Unless one is talking about something like a mugger with a knife against an unarmed civilian, melee skill (weapon vs. weapon) involves the whole body, and requires a high degree of fitness in the whole body, and persistence in training for several years. Not so with guns. (Of course there’s skill involved, and plenty headroom with guns too, but you get the point.)