You should read Daniel Kahneman's Thinking, Fast and Slow, which says basically the same thing in thorough detail. The fact that you know of some number of difficult things that you've seen and considered says very little about whether there's a cognitive bias against doing so in general - how can you even start to quantify all the things that you may have missed?
I've read it. Daniel Kahneman says something very different than what Paul Graham says. Graham is making an unsubstantiated assertion about a very specific hypothesis for which he has no evidence: that people generally fail to see ideas that would require hard work. That's not one of the many very specific biases and cognitive illusions pointed out by Kahneman which he substantiates with studies and experiments.
The unifying characteristic of the many specific biases and cognitive illusions Kahneman discusses is that System 2 systematically defers to System 1 to avoid doing work. I appreciate your point that Graham's specific claim is not substantiated by direct experimental evidence, but I think it's likely that the task of picking a business idea is subject to the same biases as any other task. It's certainly not as ludicrous a suggestion as you're making it out to be.
