Not sure I understand the next-to-last paragraph, but other than that, it seems like PG is convinced having a good co-founder is so important that focusing on finding one is the best way to maximize your chances for success (ie. achieving your "#1 goal"). Clearly, that's only true in the average case, and if you're convinced you're significantly different from that average, that might well not apply to you. The point about investor bias is spot-on, though I wouldn't say it's something specific to investors- it's just that, without looking deeply into your particular circumstances, the advice with the highest chance of being useful that anyone can give you is precisely for the average case.