"From all I have heard they both were part of a NY song manufacturing factory,
that in itself produced somewhat derivative fare within one person's work as well as within the factory.

..there was a recurrent theme that went along the lines
"Take a song, write new lyrics to it, then write a different tune around the new lyrics".

..His early work did have a sameyness quotient. Pop songs do in any given era."

.. so how is that different or inferior
to any superior minded mudcatter's much lauded time honoured folk song writing tradition...?????

These 1960's pop factory writers had talent and much more of an incentive
to make the effort to actively come up with new tunes,
or at least improved variations on those found to be most enjoyed by other folks......

Smug Folkies disdain popular songs at your peril...
lest our tradition's historic songwriting deficiencies be revealed and mocked
for the the dull pile of formulaic over-cloned tunes and poorly written words that they often/mostly are...