Most high quality beer producers don't produce "green" beer. They use higher pitch rates, higher quality ingredients, better quality control and consistency, have better equipment and usually better understanding and boat loads more experience. Again, this goes for some of the better breweries.
Plenty of home brewers produce beer with no defects or off-flavors that need cleaning up. Just not all of them and not all the time. Granted, some bigger beers do need time to mellow. There is some scandinavian brewery that holds on to their barleywines and only releases them when they think they are perfect. Their 2009 came out last fall.