If this is what they mean, I'd say that I don't mind it too much. There does reach a point where an artist ends up sounding the same with each song and each album he/she produces, so changing it up a bit keeps it fresh and relevant.
However, I do believe each artist should strive to find his/her own sound and have their own individual voice, even if he/she is experimenting with different styles. It wouldn't be good for every song in the world to sound like the exact same thing, now would it.
That's it for today's post. I know it's really short today but I took a sneak peek at tomorrow's question and it's a pretty heavy topic so I think I'll save my energy for that post. Let me know what you think, do you enjoy mainstream music? Do you wish artists would just stick to what they're most known for? Leave me a comment!