Externalities have a long history in economics. The concept has always been a somewhat slippery and controversial, but remains an important analytical tool for discussing market failures and government intervention [0].
The prospect of ecological collapse has drawn a lot of attention to the idea of negative externalities, but it's worth mentioning that positive externalities are also important in economic theory. For example, positive externalities to knowledge creation have been modeled as the engine of long-term growth by endogenous growth theorists since the 1980s (starting with Paul Romer and Robert Lucas), based on precursory work from the 1960s (e.g. Kenneth Arrow and Hirofumi Uzawa), and ideas reaching-at least-back to the work of Alfred Marshall in the late 19th c.
Still, let's hope that the global economic order doesn't depend on what economists are doing in their models :)
I'm not sure I understand your point. Perhaps you disagree with the author on the desirability of a future in which virtually unlimited energy is available to humankind in its current state (see the upshot on nuclear fusion p. 269, for example). His cautious take on our collective ability to manage our energetic needs[0] does not seem unwarranted to me.
Regardless, I think the book remains useful for its intended audiences as a quantitative assessment of available energy sources given our growth path.
[0] "The rookie mistake here is assuming that adults are in charge." (p. 134)
This paper doesn't mention her economic writings, but Jacobs thought they would end up being her most enduring legacy [0]. AFAIK they've had a much more limited impact on economics, except for a burst of interest in some circles around the 1990s (endogenous growth theory and urban econ).
For those interested in her economic ideas, I recommend reading _The Economy of Cities_ (1969) followed by _Cities and the Wealth of Nations_ (1984). For a quicker overview, here's a past submission/discussion on the topic: https://news.ycombinator.com/item?id=10834435