Externalities arguably haven’t received the attention they deserve outside of economics, but I would disagree; what are climate change discussions, if not a discussion about externalities? Hell, just about any global issue is, in part, about externalities.
Inside of economics, they have more than 130 years of work, and are taught in any intro class.
If your argument is that we are bad at correcting for them, then yes. But that is different than not considering them.
> what are climate change discussions, if not a discussion about externalities?
Climate change has been discussed for well over a half century, yet one of the main priorities of the current administration has been to hamstring renewable energy and promote coal and oil. I think it's pretty fair to say the issue is being ignored.