i agree with the spirit of this post but I think you're leaving out an important part. It seems from the other comments that the experiment described never really happened. I think if it were tried it wouldn't really work out as described. I know if i had been in that class and been in the quantity group, I would have made some really crappy, really thick pots and been done as quickly as possible in order to goof off for the maximum amount of time. If I had been in the quality group I wouldn't have theorized about it, I just would have iterated on a lump of clay. Making a pot and then not firing it or anything, just mashing it back into a lump and starting over until I got to a really good one. I think I would have learned a lot more about pot making in the quality group.
What I have read and also experienced is that producing quantity is necessary but not sufficient for producing quality. If you want to get really good at something, rather than just getting somewhat good and then plateauing, you have to not only do it a lot, but you have to care deeply about how good you are doing, identify your weaknesses and work specifically to improve those. The problem with your story is that the quantity kids have no incentive to produce quality, so they probably just won't.
For example, I'm a self-taught programmer. So, in the beginning I wrote some truly atrocious code. I got good at coding when my livelihood depended upon producing and maintaining a large complicated system. The fact that I have to maintain and improve upon this codebase in the future made me a lot better because it made me suffer for my sins, and really care about not repeating them. And obviously having my income depend on it made me care about bugs and performance and stuff a lot more. If I had just been tasked with writing a lot of code, and was paid based on line count or something, I bet I would have written a lot of code and it would have all sucked.
Ten years or ten thousand hours of "deliberate practice" - PDF link.pdf) - is what's typically talked about these days to become one of the greats. Yeah, I know - ten years??? But "deliberate practice" of any length is better than messing around and will get you good, just not world champ level, long before ten years. That sounds like what you're talking about.
Followup to: Don't Fear Failure
In the same theme as the last article, I think that failure is actually pretty important in learning. Rationality needs data, and trying is a good source of it.
When you're trying to do something new, you probably won't be able to do it right the first time. Even if you obsess over it. Jeff Atwood is a programmer who says Quantity Always Trumps Quality
The people who tried more did better, even though they failed more too. Of course you shouldn't try to fail, but you shouldn't let the fear of it stop you from tyring.
I wouldn't go as far as to say that quantity always trumps quality, but where the cost of failure is low lots of failures that you pay attention to is a pretty good way of learning. You should hold off on proposing solutions, but you also need to get around to actually trying the proposed solution.
I'm normed such that I'll spend more time talking about if something will work than trying it out to see if it works. The problem is that if you don't know about something already, your thoughts about what will work aren't going to be particularly accurate. Trying something will very conclusively demonstrate if something works or not.
Note:
I originally had this as part of Don't Fear Failure, but that post got too long.