Can the level of pleasure derived from music be measured?

It can't be quantified so it can't be measured. That is true of many of the finer things in life.

Not entirely sure what you mean by “a true audiophile hierarchy” and why one would want to establish it. Having said that and since the question deals with audiophiles and “pleasure derived from music”, a simpler and more reliable test would be to put an audiophile in front of two doors each leading to a different room. In one room is a violinist playing Bach (?), or a Blues singer with guitar, or a…..In the other room is a large collection of High End audio gear not even plugged in. Which room does the audiophile go into first and how long does he stay there before going into the other room….if ever?

@frogman 

"...or in the other room is a large collection of High End audio gear not even plugged in."

🤣

"Not even plugged in" says it all !  

I'm not a true audiophile because I don't have probes in my brain.