How useful is a production of cultural perspective in understanding the birth of rock and roll?

In his article, ‘Why 1955?’ Richard A Peterson tries to explain the start of Rock and Roll by exploring the social context of the time. He states that Rock and Roll was started by six different factors; law, technology,  industry structure, organisational structure, market and occupational careers. He debunks myths of  Rock and Roll being started by the post war baby boom and the emergence of several talented musicians.  The theory works, as it would make more sense for several factors to be involved instead of just one. One problem with Peterson’s theory is that it is all based around  the idea that Rock and Roll began in 1955. Many singles before that have been widely regarded as being the first  Rock and Roll single including Elvis Presley’s 1954 hit ‘That’s all right’, Bill Haley and the Comets with ’Rock around the Clock’ also in 1954 and even going as far back as The Andrew’s sisters with ‘Boogie Woogie Bugle Boy’ in 1940.