It seems to me they just got the scale of this completely wrong. The tubes should be a lot smaller, say a foot in diameter, and go through the air at streetlight-top level. The network would need an automated switching system to direct each "packet" from its source to any of thousands of destinations. People could pay to have endpoints in their houses or receive packages at the corner shop.
Letters, cans of beer and indeed cylindrical foods such as hot dogs, burritos or fish and chips wrapped in newspaper, could be inserted into a cylindrical capsule and delivered anywhere in the network area in a matter of minutes.