Do you have any references for this statement.

I'm not arguing there are no externalities (there are externalities in just about every choice we make). I just haven't been convinced that there are common egregious externalities at the level of dumping raw sewage into the creek.

How many sources would you like?

Of course it’s not going to be on the same order as literally dumping raw sewage into the surrounding area. But there is an enormous body of research demonstrating the overall drain of resources from economically-productive urban areas out to costly suburban ones.

Then there’s the carbon cost of enormous, congested highways and stroads where people idle in traffic for hours of their day. Or the overall inefficiency of providing general city services (water, power, sewer) to people in comparatively sparse areas (which ties back into the resource drain imposed on denser areas).

I would, personally, love to read at least one source. Which you didn’t even provide for some reason. And I mean that, I would happily read any source you provide, with a preference for more academic sources.

One it is. Link to original academic source is in the first sentence.

https://cayimby.org/sprawl-costs-the-u-s-1-trillion-every-ye...

Actually I’m an overachiever. Let’s do two! Direct academic reference.

https://www.jstor.org/stable/3325575

From the first link:

"reduce the productivity of nearby lands, for example, by [...] driving up land prices beyond what local residents can afford."

What nonsense is this?

Are you looking for references that dense population areas subsidize the less dense areas? Strong towns has lots of examples, here's one: https://www.strongtowns.org/journal/2017/1/9/the-real-reason...