also microservices in my experience worsen this sort of bitrot where the amount of usual duplication it involves means that even if you manage not to have poorly documented spaghetti magic that gets updated once in an eon in one service or two it still might be elsewhere and this

1. discourages refactoring due to the duplication
2. harms consistency
3. encourages lousiness because your stuff might mostly work on a surface level with the rest of your system because you only expose APIs and don't need to worry that much about how your methods will be called. Which might seem convenient to use and implement in an ideal scenario, but could easily become troublesome to debug if anything goes wrong.