> There are numerous technologies we have ignored or abandoned for numerous reasons.
Are there? Nukes are a thing. Chemical weapons are a thing. Cluster bombs are a thing. Biological weapons are a thing. What is not a thing that shouldn't be? We say certain things should not be a thing, but then behind the scenes we made them a thing anyway.
Nukes are barely used. The technology of nuclear detonations was practically abandoned: https://en.wikipedia.org/wiki/Project_Plowshare
On chemical weapons, most large state actors have got rid of them. Not because of any moral reasons, though, but simply because they don't actually work all that well in modern conventional warfare. This is then framed as an ethical issue, but you only need to look at where the same countries stand on e.g. landmines to realize how much bullshit it all is.
Conversely, where you do still see chemical weapons used, it's usually asymmetric conflicts where "just gas the rebels" actually works much of the time and is much cheaper than other options. Big guys can afford the other options though, someone like Assad, not so much.
More on this: https://acoup.blog/2020/03/20/collections-why-dont-we-use-ch...