You also don't get this behavior if you restrict the scope of serialization. The problem here was that Java wanted to make virtually any object potentially seri

You also don't get this behavior if you restrict the scope of serialization. The problem here was that Java wanted to make virtually any object potentially serializable. This required all sorts of deep hacks that circumvent various language guarantees and open the door to vulnerabilities (as well as encumber new features, as serialization could interact with anything). A new serialization mechanism would be restricted to classes for which serialization makes sense, basically classes that, as you say, represent data rather than data with complex behavior.