For my own sanity, I've shortened "paradigms that promote code reuse" to "paradigms". In scope of this answer, all mentioned paradigms are paradigms that promote code reuse.
What I can't picture, is an example of the opposite.
A few examples of similar questions in less abstract contexts. Maybe this helps understanding why the opposite of something isn't always clear cut.
Cleaning your house is a chore (paradigm) that enables having a clean house. What is a chore that forces you to make the house dirty?
What's the opposite of a house? It is a flat plot of land or a hole in the ground in the (flipped) shape of a house?
What did people put on their heads before they had hats?
Opposites aren't absolute; they can be specific to a particular context (added in parentheses here). What is the opposite of a man?
- A boy? (age)
- A woman (gender)
- An animal? (civility)
- A machine? (organic/artificial)
- A mouse? (courage)
This question is very hard to answer. You're asking about the absence of a paradigm.
The issue here is that an absence isn't always explicitly named. It's a matter of what's likely to happen when there is nothing explict in place (a paradigm) to avoid code duplication.
- Without a paradigm in place, anything goes.
- When anything goes, then people (especially employees) tend to pick the path of least resistance.
- For code reuse specifically, copy/pasting code and slightly tweaking it is the most common way for code reuse to fall by the wayside.
- The path of least resistance commonly chooses short term benefits (ease of implementation) over long term benefits (future maintenance).
- Repeatedly making decisions based on short term benefits over a long time period renders a codebase near unfixable.
To prevent this from happening, paradigms are put in place (ideally) from the start of the project. They effectively disallow the easy option, holding programmers to a minimum standard which avoids (or at least minimizes) the eventual future maintenance issues.
Interesting to note here is that not every path of least resistance is bad. You simply never hear about the good ones, because they never end up creating problems in the future (since they were good decisions to begin with).
When you focus on the things that cause problems, you inherently ignore the things that did not cause any problems.
This is like a doctor who complains that "everyone" is sick. They are not accurately assessing the world's population's health, they're just forgetting that the people who are not sick generally don't go to the doctor to begin with. Plenty of people in the world are healthy, but the doctor simply doesn't see them.
The only real answer to your question is projects that do not have the code reuse paradigms in place.
There is no paradigm that specifically avoids code reuse. There are, however, codebases that are devoid of paradigms and therefore are liable to eventually devolve into a codebase with little to no code reuse.
Part of me suspects that you're making inferences that are not actually implied. If I were to read a statement like:
The Flater Hospital's doctors all work to improve patients' health.
That doesn't imply that other doctors don't work to improve their patients' health, nor does it imply that at other hospitals, not all of the doctors work to improve patients' health.
Similarly, just because you know of two paradigms that promote code reuse, that does not imply that there must also be paradigms that promote code duplication (or explicitly avoid implementing code reuse).