Your post would apply if we're talking about someone like Brittany Spears, but instead we're discussing one of the greatest songwriting duos of all-time. Lennon-McCartney wrote great songs, songs that have lasted well beyond their generation. I mean, how many albums are Herman's Hermits selling these days?
You can say they co-opted McCartney, but saying they planned the Beatles is something completely different, and you haven't supported your point, not when it comes to them. Sometimes great talent rises above. George Martin certainly didn't think much of them at first. The Beatles defied their own times with what they did.
If they could purposely make this kind of thing happen, why hasn't it been done again? Sometimes I think people give TPTB too much credit. They have many resources at their disposal, but they aren't God, as much as some believe they are.