I think that varies case by case. Sometimes "intermediate" output should disappear because it's less interesting than what I had before. Sometimes it should not

I think that varies case by case. Sometimes "intermediate" output should disappear because it's less interesting than what I had before. Sometimes it should not disappear as you write. To implement that the shell prompt would need to contain a special esacape sequence as a marker and then the user can manually hide the output of the last command. Or to make it even more fancy: Hide and unhide output of any previous command.