Great article. Aside from the fact that being approached by someone "looking for a co-founder" is a turn-off (on par with being approached by someone looking for a spouse), it's also not a good sign of a successful entrepreneur. The successful entrepreneur archetype will be executing at all stages. If they believe that the lynchpin is an external person that will make it magically come together then they probably don't have the chops to make it through all the challenges that startups inevitably face. This is distinctly different from hiring an engineer, or meeting someone who shares passion and applicable skills for your idea.

As far as swinging for the fences goes, I believe that is a middle stage decision. When you have some traction, you are potentially faced with difficult choices about whether to "sell out" or not. If you are just starting out and you decide you are "going to be the next Google" that is just pie-in-the-sky dreaming, not swinging for the fences. If you want to be an Apple, Google or Amazon you will need to build it up over the course of decades through a series of successful pivots to scale up. Facebook is the most recent example, where the entire momentum of the site was imparted from the exclusivity of a truly tiny market (Harvard students), and then pivoting pivoting to progressively wider markets. For any of these companies the risks are incredible at each pivot, so swinging for the fences is more akin to building 5 startups in a row successfully. The only way you're going to get there is by building one regular small startup first and then repeatedly taking it to the next level from there. I don't think it's any different for YC startups other than that they start out with better connections, but that does not a business model make.