Quality seems to go through ups and downs, probably in line with economic cycles and periods of scarcity. Here, houses built in the 20s and earlier were made with high quality lumber that is scarcely available these days. I notice that rebuilders and renovations of these old houses are careful to maintain the base wood layers even when they completely strip the facing and almost everything else.
Also, there are billions more people who demand wood for their shelter. Is it reasonable to expect that quality of wood, which I assume is almost purely a function of time, to maintain the same accessibility?
I'm not sure that billions of people build houses with wood. It's definitely an American thing, Europe not so much (bricks and concrete.) China is concrete. India? South America? Mexico? Africa?
Because they do not have ample wood, not even the lower quality type farmed in US/Canada today. More specifically, the supply of the type of old school high quality wood being talked about in previous comments from 1920s and whatnot would certainly be impossible to satisfy global demand. Which is also a big reason why it is not used now. You can get it, it is just extremely expensive.
