Of course all pop music sounds the same - amm music sounds the asme to the non initiated
The difference with pop music is that, because its created as a commodity it's designed to sound the same until the manufacturers decide that sound has reached the end of its shelf life and decide to replace it with a "new sound" that will be put through the same process - ad infinitum
Whatever the composers and musicians want to create or of capable of creating is immaterial - it won't become "pop" (popular) until it sounds as if it will sell to the marketers
There ahre hiccups in this process - The Beatles created their own sound, which was then marketed as part of the 'Mersey Sound' and began to sounds a different 'same'
Folk songs became 'the folk sound' and became indistinguishable frpm therest of the pap
The same happened with jazz and Country and Western
Look what happened to the "new raw sound" of punk (which I always detested) sanitised and marketed as a commodity

The best of all music maintained it's identity and its uniqueness and survived apart from the machine, put the musical 'Big Brothers' always kept their beady eyes on it to see if there was any pelf to be got from it
There - got that off my chest !
Jim Carrolll