So are we saying that Lennon and McCartney were not good song writers? Hate the Beatles. Their music is annoying. But most boy bands don't write their own songs. I know they did a few covers in those early years. But they went on to write loads of their own songs. That is one skill I would give them.
But the first ever band to be honest about the music industry was the Sex Pistols. In their own words they were in it for the cash. They had a great manager in Malcolm McLaren. He would see what was popular in the day and come out with some amazing songs of that style. The greatest rock and Roll swindle. He saw gaps in the market and he would fill them. With the Pistols he knew the public were angry and wanted to vent. You had the Queen celebrating her Jubilee. They came out with God save the Queen. taken the piss out of the queen and the establishment. Mind you it was banned from every radio station and TV station. It was simply all about timing. Malcolm McLaren was an expert in timing. Bloody genius. He even had a solo career. Just to show that anybody could do it if the timing was right.