What Is Productivity in Making Movies?

My wife and I use Netflix a lot.  One of the obvious differences between classic movies and today's movies is the length of the list of credits.  Presumably part of that is giving credit to everyone involved.  But I assume, without any proof, that movies which use computer-generated graphics must employ a lot more people.  And even those which don't use CGI probably have more people per minute of film.

I'm currently drawing a blank on the name of the economist who observed that productivity in the services is much different than in manufacturing or agriculture: an orchestra playing Beethoven's 5th is roughly the same size whether it's 1915 or 2015.  I suppose that modern movies are "better" than the classics, though that's hard to prove.  Certainly they're different, sometimes faster (though watch the Cary Grant/Rosalind Russell "His Girl Friday" and you may doubt that), with different plots and plucking different heart strings.  They're definitely suited to our times and our sensibilities--again see Girl Friday for proof.

I don't know how the economists count the wages paid to the people who make say "A Good Year"--the most recent movie we watched on Netflix. (It's a piece of fluff, but very pleasant fluff set in Provence--obviously the moviemakers should have donated their efforts just to be living in such surroundings.) And how does the revenue from the movie count as well?

In the grand scheme of things, I assume economists used to assume that movies have short lives, with the cost of production and the return at the box office happening in a few months, or maybe a year.  Only the rarity like Gone With the Wind and the Disney flicks could be rereleased in later years.  But the truth now is that movies can live forever.  Maybe the money from their longer lives will diminish to the vanishing point, as piracy and innovation reduces the cost of providing the movie almost to zero, but the gain to the watcher remains significant, although not measured by economists.