It may have been a judgement call by the writer (Bostrom) and editor: He is trying to get the word out as widely as possible that this is a brewing existential crisis. In this society, how to you get most people's (policymakers, decision makers, basically "the Suits" who run the world) attention?

Talk about the money. Most of even educated humanity sees the world in one color (can't say green anymore, but the point is made.)

Try to motivate people about global warming? ("...um....but, but.... well, it might cost JOBS next month, if we try to save all future high level earthly life from extinction... nope the price [lost jobs] of saving the planet is obviously too high...")

Want to get non-thinkers to even pick up the book and read the first chapter or two.... talk about money.

If your message is important to get in front of maximum eyeballs, sometimes you have to package it a little bit, just to hook their interest. Then morph the emphasis into what you really want them to hear, for the bulk of the presentation.

Of course, strictly speaking, what I just said was tangent to the original point, which was whether the summary reflected the predominant emphasis in the pages of the book it ostensibly covered.
But my point about PR considerations was worth making, and also, Katja or someone did, I think mention maybe formulating a reading guide for Bostrom's book, in which case, any such author of a reading guide might be thinking already about this "hook 'em by beginning with economics" tactic, to make the book itself more likely to be read by a wider audience.

Agree.

Apologies; I didn't mean to imply that the economics related arguments here were central to Bostrom's larger argument (he explicitly says they are not) - merely to lay them out, for what they are worth.

Though it may not be central to Bostrom's case for AI risk, I do think economics is a good source of evidence about these things, and economic history is good to be familiar with for assessing such arguments.