So you agree that it's not an indication of quality, but claim that it's pejorative. Why?

> Morricone was more than prolific;

But he was prolific.

Wikipedia on Mozart:

Wolfgang Amadeus Mozart[a] (27 January 1756 – 5 December 1791), baptised as Johannes Chrysostomus Wolfgangus Theophilus Mozart,[b] was a prolific and influential composer of the Classical period.

British Library on Beethoven:

Ludwig van Beethoven was a very prolific composer, producing many symphonies, concertos, piano sonatas, violin sonatas, an opera, masses and several overtures.

NY Times on Bach:

If any measure of quality is applied to such a comparison, as it must be, Bach was one of the most prolific composers who ever lived; that meager output from Cöthen, for example, includes the “Brandenburg” Concertos, the orchestral suites, other concertos and the astounding solo works for violin and for cello.