I mean, i did not say that you expect swords to last years, I have been saying that it needs to be able to last a battle so there is no argument there. the concept of good enough is vis-a-vis your opponent. iron sword > bronze sword, steel > iron, forged steel > steel and so on.
And a cross bow is technically a bow isn't it? so my statement is correct, had I said slings like the romans used, then yes you are right. in this sense even Chinese slingshots are recuve bows firing pellets.
Crossbow and a bow are not the same. Not even close. Their construction methods are completely different. A bow would be made of bamboo and animal sinew, held together by animal glue. It is much harder to make, and since the glues can soften in humidity, need to be stored when not in use. A crossbow is made from wood, with the trigger mechanism --- a very precise job during that time, see the corner of this picture --- is metal.
Crossbow fires bolts, not arrows. An arrow consists of a metal arrowhead on a wooden shaft. A crossbow bolt is one solid piece of metal.
These bolts would have to be mass produced from a cast.
Then you have the training to use a crossbow. An archer is one that is trained by growing up as one since childhood. Crossbow uses, you can use farmers and train them to use it in weeks. That allows you to have a lot of crossbowmen versus archers.
Also, railway steel was imported from Russia, England and the sorts, so yes it was good quality steel. That is why you have manchurian railway incident - which was built by japan, the chinese eastern railway built by Russia - which sparked the russo japanese war. the kowloon canton railway built by the UK. so those steel are good steel comparatively.
And be it if swords are the primary armament; lets look at some historical units from antiquity:
Greek Hoplite
Primary Weapon: Doru spear
Secondary Weapon: Xiphos sword
Armor: linen armor, bronze helmet and grieves
Shield: large round shield
Republic roman legionaries
Primary weapon: Gladius sword/dagger
Primary missile weapon: Pilum javelin X2
Secondary misslie weapon: sling with lead bullets
Armor: single chest plate of bronze or iron
Shield: rectangular curved shield
Eastern Zhou heavy infantry
Primary weapon: pole arm Ge/Spear
Secondary weapon: iron sword
Armor: animal hide and helmet
These descriptions are not completely correct. Romans for example, should be divided into different eras. Early Roman Republic vs. Late Roman Empire is very different, to start with, in their armor. Cylindrical shields only appeared from a certain period of Roman history, they started with circular shields.
Zhou doesn't use iron sword, they use bronze jian. Animal hide and helmet?
By the time of the Spring Autumn period, Warring States and the Qin, Chinese were using lamellar armor, that is bronze plates that are woven into a matrix, over layers of leather and cloth. Lamellar armor is the best armor pre-BC ancients had, period. Of course, lamellar armor would only get better in later dynasties, where the count of the plates would go up from 800 to 2000 plates by the late Tan Dynasty.
Ancient Chinese used shields. There is also evidence of the use of pikes, and phalanx formations, with equivalents to Sarissa. This is from the Terracota army. The impression that Chinese don't use shields is that of the later dynasties, because lamellar body armor is so effective and thick, shields grew smaller and smaller over time till they are discarded.
Chinese armor grew thicker and thicker but something happened to cause them to grow thinner. That was already at the time when the Song were confronting the Mongols. As the Mongols were often skirmishers, having voluminous body armor proved ineffective as it often slows you down. At this point on, its about mobility and speed.
So unless you are suggesting that the ancient Chinese infantryman is less physically able to carry the weapons and gears of their eastern counterparts, then swords as a secondary weapon is not so hard of a concept to grasp.
Except that Chinese swords were typically longer. By the time of the Tang Dynasty, Chinese dao were like 5' in length. These swords are not carried on the hip but on the back. These are not your secondary weapons.
There are swords only infantry such as specialized double handed sword infantry like zweihander, or skirmishers but they are not numerous and typical. even infantry using zhanmao dao vs. cavelarty is highly reliant on the polearm formation to break up cavalry charges to be effective. It should be evident that a wall of lancers will hit the infantry with the double handed sword first with their lances before the infantry can swing their sword. the double handed sword is only effective when the cavalry run past the infantry squares.
They are quite numerous by the Song Dynasty as required formations. Even a Song Emperor personally intervened in the design process for a new sword to deal with the heavy cavalry of the Jin and the Liao. These northern kingdoms were using Cataphracts that are heavily covered by lamellar armor in addition to the rider bodies themselves, and are impervious to all Chinese weapons, even crossbows. The result is the Zhanmadao, and the Song had special formations of very brave men to handle it.
Now as for "swinging" the long sword. Typically, long swords are also used like lances.
As for cavalry lancers, the problem of that if the lance sticks through its victim, its going to get stuck, and the violence of such will also take the rider down. Hence why the northern cavalry typically uses sabers, curved ones at the end --- the design would later influence Chinese Dao in later periods, as well as Middle Eastern swords.
what people generally forget, and i blame TV and movies, is that the Chinese battlefield is not made of cold steel for a very long time. the Song had invented cannons and the the last 1000 years, three barrel pole guns are very common during the song and the ming.
This is from the fire dragon manual from 1300s/1400s
you see Chinese musketry and the secondary sword on their belts.
But we are digressing, my point is, making steel is hard, making good steel is harder.
What you didn't get as a fact that Qin -> Han saw a shift from using bronze to iron to steel in a mass fashion. That's the archeological evidence behind it. The lamellar armor for example, shifted from using bronze plates to iron or steel plates. The Ge, which used to be made in bronze, shifted to steel. By the late Han Dynasty, the steel Dao, in the two handed form with the ring dowel, is the prominent CQC weapon, replacing the bronze jian. Since samples of these swords are found all over, these swords are not likely to be rare.