Vivek Wadha: "You learn little by writing code."
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Maybe this is insufficient as an alternative education (I'd really love to see some numbers for that but, then again, wouldn't we all?), but it's silly to bring it down to "writing code".
There's something very different between looking at the consequences of other people's decisions vs. having to weigh the evidence yourself, pick a course of action, commit to it, and then deal with the results.