Don't worry. Once swords would once again become useful on the battlefield and in dark alleys, this skill will resurface and thrive again.

Chances for it are not small enough.

I had a Japanese friend who says he had a real Samurai Outfit and sword. It was giving to him by his Grandmother who had inherited it from her family. When Lord of the Rings came out, a different fellow I worked with bought a replica of Anduril Sword from LOTR's. There was a discussion at work about how good the Anduril sword was which led to a challenge. I was to wear the Samurai Outfit since it was my size and use the Samurai sword and he was to fashion some armor and use the Anduril sword. He backed out after his wife threatened him and me.

there is a very good chance that the replica sword is made from a relatively cheap stainless steel with uniform hardness through the blade. While the excerpt below is about cheap replica katanas it can apply to any such replica blade:

https://en.wikipedia.org/wiki/Japanese_swordsmithing

"Most cheap reproductions are made from inexpensive stainless steels such as 440A (often just termed "440").[45] With a normal Rockwell hardness of 56 and up to 60, stainless steel is much harder than the back of a differentially hardened katana (HR50), and is therefore much more prone to breaking, especially when used to make long blades. Stainless steel is also much softer at the edge (a traditional katana is usually more than HR60 at the edge)."

So, i'd not risk using such replica sword against a real world sword :) On the other side one can imagine how a modern sword can be made - say carbon fiber core inside titanium monocrystal envelope with fused, like laser sintered, ceramic/nano-diamond skin and edge. And resorting to cold weapons may be a reasonable alternative to guns in the future conflicts inside space stations and planetary bases.

Wielding a sword in zero-G would be problematic. As you swing the sword, your body is going to torque in the opposite direction (conservation of angular momentum)!

>your body is going to torque in the opposite direction.

and it may make sense to have an additional blade attached to the other end of your body. The art of sword fighting in zero G or low G - imagine on Moon like those long high jumps from Crouching Dragon :) - would look different.

Uh oh. You both are lucky that he had such a wife, because there was a big chance to leave you both injured, or worse. Even the best armor is not absolutely damage-proof. Also, such "test" is rather pointless if done not between trained swordmen.

Yeah. If nothing else, imagine how it would feel to have damaged an heirloom samurai sword by hacking into a cheap movie prop sword and chips the metal.

I was told that with gemstones, a stone of lesser hardness can never scratch one of greater hardness, no matter what. I wonder how that relates to a cheap potmetal sword and a strong, hardened one...

That is basically the definition of hardness. It doesn't make gems indestructible; they can be worn down like anything else. We cut diamonds even though we don't have something harder to cut them with; it's just much harder than cutting softer stones with diamonds.

A cut gem's sharp corners will be worn down over time by the paper the gem is kept in. Paper's not that hard.

(And of course, even if scratching were completely impossible, gems are still easy to smash. There are all kinds of deformations that aren't scratching.)

I've had a very nice kitchen knife get stuck in an unexpected bone. The blade lost a big chip, because it twisted in my hand after sinking in a little. But no, the bone didn't scratch the blade.

You can easily smash a diamond with a hammer, even though the diamond is far harder than a hammer.

Aside from that, metals quite often gouge and chip one another, and 100+ year old swords are not automatically stronger or made of better materials than present day pot metal.

After a certain point, a sword is more valuable and useful as an art piece than as a weapon outside of emergencies.