I'm willing to say that, yes, if you focus on something long enough, you probably will make great strides toward competency in it. The 10,000 hour thing seems pretty valid. But the question, to me, is: why? The opportunity cost is quite high. Am I better off spending 500 hours focusing on learning to schmooze and network, or spending that 500 hours focusing on my technology skills and, notably, creating valuable product in that time? Improving a weakness for the sake of eliminating that weakness is what strikes me as snake oil. You're not invalidated simply because you're weak in an area, and often it's far more valuable simply to be aware of a weakness than it is to eliminate it.

Further, I don't really think pg's point was that you can somehow follow a guide to resourcefulness and become resourceful

I agree. My takeaway from pg's essay was that founders who are both technical and socially/schoozily/network-ily gifted will be more successful than those which are merely technically gifted. That was sort of a "no duh" for me, but perhaps there's an insight there that I'm not seeing.