I think I didn't quite understand your question. Perhaps it comes down to this problem:

Do you want to fight a war in Lagos? Or a war against Lagos?

The premise of urban warfare is that you can conduct a military action within an urbanized area without reducing that urbanized area to a paintball arena. People lived in Sarajevo while Serbs and Croats were busily settling the score for 200 years of history, and continue to do so. A lot of it is still pretty shot up and it'll never be the same, but it's a long way from The Blitz.

The argument of the paper is that above a certain point, "Sarajevo" is wishful thinking and "the Blitz" is the end result. Basically, you're going to quagmire above a certain population level regardless of your actions.

It's interesting to me because architecture has far more of an impact on military strategy than a lot of people realize. Geoffrey Parker claims that the invention of the Star Fort effectively created the professional army and, therefore, the modern middle class. This is the US Military arguing, essentially, that above a certain size, cities cannot be held. That's almost a parallel conclusion to the military assessments of Star Forts: above a certain level of fortification, cities cannot be sieged.

That's the true conclusion of the article: we no longer really know how to conduct the battles we can expect to fight. I don't know nearly enough to question whether this conclusion is correct, but it's a pretty stunning one to make. You're talking about a substantial percentage of the modern military-industrial complex being spent on tactics and armaments that will not, in fact, be useful.