Well I don't know about everyone else around, but I'm a European myself so I certainly don't view this from the USA view on it. So while I think it's undeniable that you're obviously right that it's hard to not at least tear some things down to for instance get rail lines some what deeper in to cities and such at not all to excessive a cost. Quite a few European countries never really want all that extreme on it either, certainly not like the USA did, thus leaving quite a bit of historic cities still actually fairly intact (Well aside of the ones blasted to pieces in wars of course).
That is a very important asterisk- most European cities
were beaten up pretty heavily in World War Two, if not before. And quite a few more underwent considerable rebuilding late enough in the 19th century that the necessary basic transport corridors were already in place by the 20th (see for example Paris with its boulevards during the rebuilding by
Haussmann.
And some of us will say "oh, Haussmann was just trying to make the city accessible to crackdown troops instead of having easily barricaded alleys," but the thing is, pre-1850 Paris was objectively a very crowded city and that objectively did contribute to problems of sanitation. Crackdown troops aren't good for the working class, but neither are cholera epidemics. And, again, the Walled City of Kowloon does not represent the ideal model of urban development.
Europe has plenty of cities with surviving
chunks of city centers that date back to the early 19th century or earlier, but the fact that you can even walk into those cities at all and find buildings and infrastructure built after 1945 illustrates that this kind of thing still has to happen in some form and on some level.
I'm very clearly not saying "everything must be torn down," I just want to emphasize that. But
some things have to be torn down. You cannot get from 1800 to 2000 without some cycles of destruction and creation, any more than medieval cities were truly static and unchanging in their own day. There's survivorship bias in that we notice the buildings that stand for several hundred years, but don't notice the areas where buildings
didn't stand for that long.
Again, creation and destruction are both, and both have always been, parts of urban life. What matters most is ensuring that the destruction is not pointless and (hopefully) is not used as a club by powerful elites to hurt underclasses.
Due to the above the city renovations in Russia that are being done right now leave me kind of with mixed feelings actually. I originally thought when they said renovate in the plan, they meant renovate but I guess that was a bit naive of me. But it's probably the best you can hope from from the Soviets with in political reality, though can't help but suspect they're greatly misjudging what actually really is important and what isn't. Though well, that's just how this quest has always been I guess. Just have to get through things best one can. Still a shame so much of the historic cities are probably being destroyed at substantial cost when they probably didn't have to be damaged nearly so much though.
Well, I know a lot of what's being torn down here is Stalinist-era barracks housing and tenements, and I'm not sure that counts...