The guys that are truly THE be all and end all play by themselves. No other band members needed/wanted. They don't sing or need to. They just play great big halls and sell out everynight!
It ain't about being great. It really isn't about ego either. The truly great ones have a close knit group of people around them, usually friends and play for and off of each other, therefore all members in the band could be considered great by default. That is when the magic happens and it turns into a show. Nobody in the band says to anyone else "Your playing SUCKED" and means it, the members play and have fun.
Greatness is in the mind of the audience. If you have a bunch of guitar players having a contest to see who is the best they are probably laughing at the joke of it all. They know the truth, there is more to the show than an axe player.
No matter what style you like to play or whom you emulate matters. What does matter is being able to learn and build on what you have with other people that want to do the same. If you want to stand alone, you probably will.