Making a knife that _keeps_ sharp; and that will not chip/shatter/handle won't disintegrate is the difficult part.
(You can also argue about blade geometries, how thin the blade is etc for hours; but "can this be made sharp" is not a problem with cheap/bad knives, generally.)
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My (very limited!) understanding of knife steels is that "powdered steels" are not what you'll find in a random big box store; but rather more expensive, "fancy" lines.
You don't have to spend $450 on hand-forged, artisanal blade from Japan, but a $50 buck no-name is not going to be Buy-It-For-Life powdered steel knife either.
I have tried sharpening them, I have a Lansky knife sharpening kit/jig that I use for my other knives, and it works fine at least for the first or second time, but spending ~20 mins on an $8 knife instead of getting the spare out isn't something i choose to do.
(And now I've typed that out, I feel somewhat guilty and wasteful about it...)
It's only wasteful if you're throwing them in your trashcan.