For example, if a student pays someone else to write an essay, nowadays that gets classified as plagiarism. But it's hard to see it as a theft of ideas, any more than it's theft if I buy something from a shop.
For example, if a student pays someone else to write an essay, nowadays that gets classified as plagiarism. But it's hard to see it as a theft of ideas, any more than it's theft if I buy something from a shop.
It is not the same as copyright infringement - although it might be both at the same time if you copy something without permission and publish it under your own name.
Plagiarism is not always illegal. Publishing a book which is ghostwritten by someone else is not illegal AFAIK (as long as they get paid). But in education and research it is illegal - and they don't care if you bought the material fairly, the point is that decisions (grades, hiring, funding etc.) are based on the assumption that the material reflects your abilities.
So it is not really "theft of ideas", it is "faking credentials".
While academics have high morale on not stealing more than four words in the same sequence, they don't have any issue putting their names first on some engineers idea.
Where I would agree with your general statement is the concept of "self-plagiarism", typically defined as submitting the same work for credit in multiple forums. Plagiarism requires a third party whose work is being passed off, and self-plagiarism is an oxymoron.
I would prefer to reserve "plagiarism" for the case where the true originator of the ideas is potentially being eclipsed.
(Incidentally, according to my local university's academic misconduct policy, if the vice-chancellor uses a speechwriter without crediting them they are indeed a plagiarist. That doesn't seem entirely unreasonable to me, though I suspect it may not be enforced, but I would prefer to use a different term.)