The very fact there are articles explaining previous solutions to these problem domains is why I just don't believe anyone would ever take a year to get up to speed with something an expert could do in one day.
I can make a great spell checker or a great anti-spam program that takes an expert a day to program in less than a year by just googling it.
There are so few programming domains that aren't fairly transparent where a domain expert has such a massive advantage that a domain novice couldn't gather sufficient knowledge in a year to rival the other programmer's one day effort, given the same level of intelligence, etc.
When it comes to spelling correction, there is a lot of literature on how to do it. So that example I grant you. But could you, before Paul Graham's article, have written an anti-spam program that is that effective? Seriously?
Another one: http://www.paulgraham.com/spam.html
For many years hundreds of programmers worked on anti-SPAM systems that weren't as effective as the very simple method PG proposed.
If anyone else can think of more I'd love to know them.