Semantically, pg said that it's empirically difficult for one person to start a big company on their own. This does not preclude the possibility of it happening. It's just rare. And his evidence is the fact that most large companies were started by multiple people. You may not like the implication, but his statement is factual. He was careful with his words and he's right.
You also may have misinterpreted the spirit of what pg said. He didn't say that a cofounder was the only path to human happiness. He didn't say anything disparaging about single founders. He just said that most of the successful startups that he's seen have involve multiple people, without publicly taking an opinion for or against the issue.
FWIW, pg's logic isn't entirely sound either. Saying "most of the successful startups I've seen have multiple founders" is no more valid than saying "Most of the corporate CEOs I've seen have been white males, therefore being a white male must be one of the criteria for success."
It doesn't matter how many people are involved in the founding of a company. If it's the right idea at the right time with the right execution, things will be fine.