Because the system can't be intelligent enough for that.
Say the process wish to write to a particular file; — how far up the directory tree does the system ask for permission?; only that specific path? the home directory?; how can the system know this?
Of course, the other issue is that, say the system be implemented so that the write call blocks until the permission be given, that they will timeout with an error because they have limits on write calls that take that long, and assume there is something else that is wrong like mechanical storage failure, if a simple write call truly take seconds.
Say the process wish to write to a particular file; — how far up the directory tree does the system ask for permission?; only that specific path? the home directory?; how can the system know this?
Of course, the other issue is that, say the system be implemented so that the write call blocks until the permission be given, that they will timeout with an error because they have limits on write calls that take that long, and assume there is something else that is wrong like mechanical storage failure, if a simple write call truly take seconds.