I loved the collection of photos, in fact, think I saw the house I grew up in in those pictures! Well, not really, but like has been stated before, many of those houses seem to look alike... I guess that throws a wrench in to what we think of as these new cookie-cutter homes; it's been going on for over 100 years like that!
I know some people have wondered why these homes cannot be salvaged and renovated and restored to their original grandeur but having grown up in a house like this one here:
I just cannot imagine that it would be economically feasible. The plumbing in these houses inadequate to say the least and much of the electrical system would need to be re-wired to bring them up to today's codes and many of the rooms will have only one actual outlet. Generally, there is absolutely zero interior insulation and if you're lucky, somebody may have added some exterior insulation sometime along the way. Inside the rooms, there are likely 10 coats or so of lead based paint with a few layers of wall paper thrown in between them for good measure. Lastly, without the proper maintenance over the past 100 years or so, the plasterwork is probably just crumbling away.
If somebody wanted a house with similar architecture in one of these locations, they could probably build from scratch for much cheaper and still get a design that looks like these do. If you are lucky and there isn't much warping due to water and freezing and thawing, you could salvage some of the wood materials from these old homes to put into a new one (e.g. wide wood floorboards, solid wood doors for the interior, bullseyes and frames from interior doors/windows, etc...) and still end up ahead of what it would cost to actually rehab one of these homes.