I believe music quality can be improved quite a bit by using the correct software. Tones can be enhanced, making them clearer and sharper, notes can be extended, and sounds can be distorted. Software is capable of a variety of enhancements that could not be achieved by any other method. The software also aids creativity.
I don't think it can be pushed much more,but if you heard some of these people sing without some vocal editing. It would be a good laugh. Its all done through the magic of the pc now and most artists couldn't hack it 50 years ago, I think those artists are much better than the fools today.
I definitely think that the quality of music can be improved when using software. Sometimes music can be enhanced using some of the technological advancements available today. I think that a lot of studios can use some of these enhancing software to make some older music files sound a lot more crisper.
Yes, I feel that music quality can really be improved by using software, because it can help people who can't really sing. Ashlea Simpson was a good example of this. Her singing was pretty terrible, really, but with enough special effects through the magic of computers, people wanted to buy her records.