Yeah. This technique is called "comping." It is also used with instruments.

Literally all vocals are processed in some way in a computer program (for example Pro Tools and Logic). Reverb and compression are two of the most commonly used effects (could use reverb to make it sound as if the vocal is in a big hall; compression can make it sound fuller, fatter).

As Giga pointed out, the frequencies of a sound can be changed. If a vocal is muddying up a certain part of the stereo spectrum, they can put said vocals through a filter to cut out those specific frequencies. This doesn't just appy to vocals either. These are production techniques for all instruments.

SurrealDreams made a good point in mentioning how such things can be used creatively. Just take a listen to one of BT's vocal tracks. Some of the stuff he does is just insane.

The point of using all of that stuff is indeed to make everything sound as good as possible. This isn't anything new though. It's just that the platform in which it is being done on is moving in the direction of software, rather than hardware.