While it is true that you'd need to know fewer people, everyone would still need to know everyone else indirectly in order to be admitted in the first place. This is a requirement for the security of the network from infiltrators: someone already on the network would necessarily need to provide you with a "secret" of some form.
By contrast, with a more standard sneakernet, you'd need to know everyone you're in direct contact with -- but that number is typically kept fairly low for social reasons anyway. Data would be distributed more widely by passing through several intermediaries: Bob copies all of Alice's data, then Carol copies Bob's, and now Carol has Alice's data without necessarily having met. This is how people used to pirate software before network access was so common, and it actually worked pretty well.
Want to know who to blame for all the old games asking you to "look up this word in the instruction manual"? It's people doing this.
That you need to know fewer people is significant, and even more so is that you not meet in person that is why the "Dead Drop", "Dead Letter Box", etc is such a common tactic in espionage. deadSwap is a file sharing system/ urban game based on the concept. When done correctly it is very effective and very difficult to sting, thus it has been a standard in spycraft for decades.
By contrast, with a more standard sneakernet, you'd need to know everyone you're in direct contact with -- but that number is typically kept fairly low for social reasons anyway. Data would be distributed more widely by passing through several intermediaries: Bob copies all of Alice's data, then Carol copies Bob's, and now Carol has Alice's data without necessarily having met. This is how people used to pirate software before network access was so common, and it actually worked pretty well.
Want to know who to blame for all the old games asking you to "look up this word in the instruction manual"? It's people doing this.