Grain structure seems to have improved the most in the absence of significant high frequency detail:
https://caps-a-holic.com/c.php?d1=16848&d2=16550&c=6244
With regard to the available detail in the negative they just did not have that much to work with.
I have been guilty of that, too but yeah, you're right that we should try not to do that.
Back to Harold and Maude: I have the Criterion release and I was wondering how much of an improvement Paramount was able to get out of this one. Apparently not much so that will be a pass for me.