It seems to me that so much that's nice fails to be preserved because growth expands outwards and the inner city areas are developed into behives for the swarms so that growth can be satisfied.
Myself I think there is space for a bit of mixture.
I first came to Joensuu (Finland) in 2006 and was very pleased to see a nice balance of medium density amid the historical large homes built back in the formation of the town. One such place I liked was this one:
Perched on a large block when the area (just 3 blocks from the center of town) was largely rural
it had a what must have been in its day a grand entrance
which ironically is about the size of the smallest of apartments in town now ...
This is the first time I've seen it empty, and the owners have allowed it to run down, which means to me that its not far off demolition. I suspect that in a not too distant future there will be someone who wishes that it was still there, and they would pay handsomely for a patch of real estate within walking distance to the University which had the character and class of this place.
Well ... I guess that's progress