I think chain cleaning technique & practices is partly a function of how you use your bike. As a commuter, I clean my chain once a week and wipe it down any day it rains. If it does develop visible rust, such as if I forgot to wipe it down on a rainy day or if there's snow, ice & salt, I take the Simple Green to it and use the chain cleaner tool. Otherwise, I just run it through a rag.
I am not so patient as to wait until it is completely not black. That takes forever, and a few applications of oil. Yeah, I guess the purpose of the lube is to clean the chain more than it is to lube moving parts. It took me a while to figure that out. Leaving oil on the chain just gives the dirt something to stick to.
I replace my chain every 1500 miles. At the bike shop we check it with the tool and it's approaching 1/8 inch at that point. I was so proud of myself because my cassette lasted 5000 miles, and the mechanic said that was due to my diligent chain cleaning!
2009 Trek 7.2FX WSD, brooks Champion Flyer S, commuter bike