A great performance does nothing to make a mic "work" any better than a lousy performance, other than the fact that it captured a great performance.
I have to disagree. A mic is not a point-and-shoot camera that captures a performance. To a vocalist, it's a tool that is used as a component to create a great performance. It's an instrument that the vocalist plays. Is the way a guitarist frets and picks a guitar part of the performance? Yes. If you ignore the proximity field of a mic, and hit it too hard or too soft, you don't know how to use that mic, and the performance will suffer. If a vocalist sings the same way into every mic, their mic technique is not very good, and they have a few things to learn. And if you think that 2 different mics will give the same results from the same vocal performance, you may have overlooked one of the fundamental differences between amateur and professional singers.
You have to hit tube mics a little harder, to overdrive them a bit on purpose. You have to soften aspirated consonants more on small diaphragm mics, because they are prone to popping. You have to be careful when flirting with the proximity field on hypercardioid mics, because the proximity effect is more abrupt than gradual, and movement variations between on and off axis will suck, wheras cardioids tend to be more forgiving.
If the mic was 10' from the singer, what you say might be true, but as long as I am 6-12" from a mic, I need to know what kind of polar pattern it has, where the proximity field begins, and how abrupt it is. That's one of the reasons I was very surprised when one frequent poster here said he prefers to record vocals with an omni. Well, not me. The proximity effect is my friend, and if you take it away from me, it's like taking compression away from a bass player, or distortion from a lead guitarist. The big difference is, though-
You can compress the bass player later, you can reamp a guitar (although it will still affect the performance), but you can't add proximity effect in post production. Thanks, but no thanks, I will keep my nice directional vocal mics.-Richie