Well, not every engineer is experienced enough to immediately notice all potential problems which can arise in production. It worked in microservice A, why won'

Well, not every engineer is experienced enough to immediately notice all potential problems which can arise in production. It worked in microservice A, why won't it work in microservice B? It all comes down to expertise. The average engineer is probably better off relying on a versioned, upgradable dependency maintained by more experienced folks than on copying code snippets here and there.