I suspect the reality is the human cost of dealing with versioning in an API is the problem.
Well, yes.
- You release a new API version. Now you find a bug. Now you need to fix the bug twice.
- You decide to change the way a feature works. You can't get rid of the old code. Now you have two copies of the same API that work differently and need to be documented and run tests. Perhaps they each need to maintain their own data models.
- Every API version means more code. That's more room for security vulnerabilities.
Comments
Well, yes.
- You release a new API version. Now you find a bug. Now you need to fix the bug twice.
- You decide to change the way a feature works. You can't get rid of the old code. Now you have two copies of the same API that work differently and need to be documented and run tests. Perhaps they each need to maintain their own data models.
- Every API version means more code. That's more room for security vulnerabilities.