How useful is Peterson's production of culture perspective in understanding the birth of rock 'n' roll?

I have found that Peterson’s account of the reasons for the development, and popularity, of rock music in the 1950’s using production of cultural perspective to be intriguing and informative.
I feel the he demonstrates the symbiotic relation ship between Broadcasting Industries, Record Company and Technology aptly. Also his historical reasons for the rise of any alternative style of music, not to the likening of ASCAP executives, being understated until the 1939 licensing dispute, which of course led to the founding of BMI paving the way for Jazz, R&B, Gospel and Country to come together and form Rock sixteen years later was fascinating.
However there are problems with this article. For example in the introductory foot notes he says that ‘Rock’ will be used as an umbrella term for all forms of rock. Surely there must be some distinction between rock music that comes from a country, gospel, or R&B background? Also he disregards technological developments of instruments themselves, which made recording and performing easier. He also doesn’t explore the changing style of music, referring only to the ‘crooner’ style of the 1940’s.

What is popular music?

Popular music can be defined by several criteria in several different ways. For example it can be defined historically, by the means in which it is preformed, produced and marketed or the way in which it is consumed. Popular music can be categorised by class, audience and cultural capital. However each of the above methods of categorisation, definition and analysis have their own floors.
If for example we were to define popular music as mediation between high and low art, where do we place Nessun Dorma performed by Pavarotti that became a number one chart hit in 1990 following its use as the world cup anthem or the dance tracks that make use of samples from opera or orchestral pieces for example the techno remix of Beethoven’s symphony number five, first movement.
Looked at in terms of industry and quantitative measurement, we encounter problems when it becomes clear the what sells is not always good or that popular e.g. the ‘Crazy Frog’ or ‘Flintstones Theme Tune’. Popular music can only be defined by acknowledging the wide spread of cultural, ideological, class, industrial and technological elements that form the ever changing, fluid entity that is ‘popular music’.