The emphasis in the early days of songwriting was on a great melody. Music has become more rhythmic in recent years. I'll leave it up to you to decide whether this makes it easier to create what is considered popular music nowadays.

The music industry creates music with the goal of becoming as mainstream as possible. This is accomplished by creating generally unartistic, overly repetitive music that follows current trends. And what's trendy? Women showing skin and obscenity. That's what they do. It sells and they make it.