Don't get me wrong, I like density and I like skyscrapers (when appropriate), not just from a personally subjective standpoint, but also in the objective functionality and purpose of cities. I also have found myself agreeing wholeheartedly with nearly all of his previous writings and papers even saying many of the same things that he does. But his argument for unrestricted height is so facile, redundant and trite that the book nearly took a swim in the rooftop pool of the high-rise I reside in out of frustration because the rest of the book was quite good.
The most glaring offense came when he decided to take on Jane Jacobs herself. I don't deify her and can find little nigglings to quibble with here and there within her many writings, certainly. How on one page can Glaeser cite her suggestion that neighborhoods function best between 100-200 residences per acre only to turn around on the very next page and distort her argument that she would prevent a 40-story building in order to save a 1-story building. 100-200 residences (not just residents) is pretty extreme levels of density and impossible to support in a neighborhood full of 1-story buildings.
It's the equivalent of me saying, Glaeser wants every building on every block to be Burj Dubai. It's a useless strawman and undermines his argument to extrapolate the views of the opposing view to the point of ridiculousness as if that somehow strengthens your own point. False. I hope Glaeser knows better than this and it is simply a dumbing down by his editor to reach a broader audience.
It leaves out rather than acknowledging the primary weaknesses of skyscrapers that, in a free market, density is a direct by-product of desirability. And that the height, disconnection, shadow cast, and micro-climatic effects on the ground plane undermine that same desirability achieved through the existing spatial integration and centrality of the site.
Nor, and probably even more damning, does he acknowledge the diminishing returns on density that anything over 60-80 dwelling units per acre, the benefits of density tend to flatten out. As Geoffrey West talked about in his TED presentation alluding to a unity of knowledge, of life, all growth in living networks is sigmoidal, or the shape shown below. As West points out, it is why public corporations fail because they stop returning the same rates of growth forever. Similarly, density over a certain point just becomes undesirable for a variety of reasons and the gains are minimized likewise.
In the end it does no justice for what ought to be his goal, that of improving cities, which many of his early anecdotal supporting evidence supports incredibly well. Nor will it help his case of mattering over the long-term instead simply pigeon-holing him into a sort of single issue proponent rather than a measured champion of properly functioning, sustainable, enjoyable, desirable, productive cities.
In doing so, he loses his most significant point that cities in actuality are invisible, they are the interconnections between participants and the buildings and infrastructure are all merely the physically constructed tools in support. That will carry on far longer than the rest of his book will, in the same logical progression that Jacobs' Death and Life spawned with complexity thinking.
It's this kind of poorly argued, simple-minded view of both urbanism and density that lead to density without urbanity. Towers and height, but no complexity or interactivity with context. It's more complex than that. It's also more simple. His book doubles back on itself to undermine its best point that cities are about the invisible only to dwell monotonously on the physical, what he suggests is merely a symptom and outgrowth, and quite rightly.
Instead, he would've been better off spending more time on the complex systems visible and invisible such as the increasing role of the internet on urban form or what infrastructural networks actually look like that make appropriate platforms for high-rises, for increased demand through desirability and opportunity through spatial integration leading to the high degree of accommodation that is a skyscraper.