This only leads to bad code when people get to afraid to refactor things in light of the new requirements.Which sadly happens far to often. People seem to like to keep what was there already and follow existing patterns even well after they are no longer suitable. I have made quite a lot of bad code better by just ripping out the old patterns and putting back something that better fits the current requirements - quite often in code I have written before and others have added to over time.

Yup, this is part of what's lead me to advocate for SRP (the single responsibility principle). If you have everything broken down into pieces where the description of the function/class is something like "given X this function does Y" (and unrelated things thus aren't unnecessarily coupled) it makes reorganization of the higher level logic to fit the current requirements a lot easier.

For instance I see this a lot in DRY code. While the rules themselves are useful to know and apply they are too easily over applied removing any benefit they originally gave and result in overly abstract code. The number of times I have added duplication back into code to remove a layer of abstraction that was not working only to maybe reapply it in a different way, often keeping some duplication.

Preach. DRY is IMO the most abused/mis-understood best practice particularly by newer programmers. DRY is not about compressing your code/minimizing line count. It's about ... avoiding things like writing the exact same general (e.g., a sort) algorithm inline in a dozen places. People are really good at finding patterns and "over fitting" making up abstractions that make no sense.

For instance I see this a lot in DRY code.

DRY is one of the most misunderstood practices. If you read pragmatic programmer (where DRY was coined), they make it clear that DRY doesn’t mean “avoid all repetition at all cost”. Just because two pieces of code look identical doesn’t necessarily mean they are the same. If they can grow independently of each other, then they’re not repetitions according to DRY and should be left alone.