Alot, yes. All, no. Same with the rest of the list I included. My point is that not everyone can do everything. Thats why there's a large market for session musicians and beat makers. A great song is a great song whether the performer wrote it or not. Most songwriters are not performers which is why they do what they do, same with entertainers. Respect should not be lost for any party that took place in a stellar composition/recording, thats all...