All these are fair and good points. But all of these are still workable problems that should be very much in the capable hands and constraints of the operating

All these are fair and good points. But all of these are still workable problems that should be very much in the capable hands and constraints of the operating system and "app bundle runner" (call it) to deal with. Your points are all solved by using the user's home directory, very true. But the problem simply remains -- I think this is my main point -- that the "App bundle" has failed the user by not allowing for cleanup of everything that the application has created. If an application can simply write any executable into any user directory it wants, there's no code signing or integrity checks on the app itself that matters. Applications should be treated as hostile, just like a user is treated in a multi-user system. I think it's a failure of an operating system to not be completely in control of the limitations and installation of any program. It's also a failure of the developer community to not stand up and insist on this too. A sand-boxed model is what we should all be striving for here. Force the bad actors out. I'm not a Mac developer (obviously). But I am an old Unix neckbeard. So I get all of your points; Unix invented this problem. In a multiuser system, individual users are treated as hostile. Going forward, so too should applications. That's the failure in all of this (and it's been with us a long time now). Our security model is based on not trusting users, but in trusting applications. This thinking was born in the 60's when users couldn't install/execute any random download. It's interesting that the unix model of security is hurting us more today than helping. The time for sandboxed applications is definitely overdue.