yeah...it's also a matter of lots of practice.
Remember how long it took to learn to play guitar? It's kinda the same with doing vocals with a Mic..

Or, in the case of a lot of recording artists these days, just do numerous takes on a dozen tracks which are then edited together so you get the best overall performance...using de-essers, compression, reverb, autotune, and other various 'sweeteners', chorus effects, sonic maximizers, harmonics...tube pre-amps and $3000 mics...