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Strong Towns is just one perspective with a strong agenda. I began doubting everything they publish when they got all the important details completely wrong in a story about my home town.

The money that goes to cities is paid by the employers of people who commute from suburbs, and the businesses those commuters buy from. The mental and physical space of living outside the city is essential to maintain the productivity and sanity of the urban workforce. Cramming all those people into cardboard "luxury" apartments where their kids have to listen to their neighbors fighting or banging sounds like a great way to end a population by ending parenthood. Which is exactly what is happening.

> Or what if Dark Matter was lots of Black Holes?

Black holes are indeed[1] a dark matter contender!

Just because the best explanation[2] we have right now is cold dark matter (CDM), doesn't mean physicists are content. They're looking for new ways[3] to probe not just CDM but other dark matter models as well, like primordial black holes[4].

Dark matter is by no means a settled topic.

[1]: https://en.wikipedia.org/wiki/Primordial_black_hole

[2]: http://pirsa.org/20040087/ "Dark Matter: A Cosmological Perspective", nice colloquium talk giving overview of what we know about dark matter.

[3]: http://pirsa.org/20100052/ "Strong gravitational lensing as a cosmological probe: new ways of constraining dark", random technical talk about new way of probing CDM.

[4]: https://arxiv.org/abs/2002.12778 "Constraints on Primordial Black Holes".