-Mod Hat On-
This is a hot button discussion, and it's already punched a lot of nerves.
There have been plenty of responses that offer different reasons while also offering different perspectives. It would probably help to reword the question into a broader statement rather than a closed one:
"Why do webcomics/artists have varying degrees of art quality?"
"Is it possible to improve while trying to constantly update webcomics/constantly put out artwork?"
Again, the previous responses are applicable to these new questions, and it helps to paint a bigger picture for what goes into art qualities. Remember, every artist goes through their own journey, and most of the time, we only see the end goal (yes this also includes professionals). You cannot compare everyone to anyone, especially when goals and paths are so different.
I don't think the thread needs to be closed, as most have offered good insight that a lot of people need to understand. But I do want to remind everyone to stay civil.
Stay frosty. 