I suspect this is the opposite in areas of the USA that have seen population declines. There is virtually nowhere in the USA in the 2020s that looks like, say, Ogimachi Village. And even in, say, the 1920s, so much forest had been cut for agriculture, logging, mining, and soon thereafter for the first suburbs, that I can't imagine human development had any positive effects whatsoever on wildlife or biodiversity.
I's not that simple. Look at New England. Initially de-populated and left to grow over thanks to western agriculture then intentionally key that way by environmental policy. It's not inching toward anything resembling pre-colombian forests. It's turning into an impenetrable thicket. But hey, plenty of food for the asian long horned beetles and gypsy moths so that's a win. /s
There's a lot of bits of biodiversity you don't get without humans putting their thumb on the scale and forcing a different equilibrium.
I wonder how much this is a factor of time. After significantly more than 1500 years of intensive human management, the ecology of Japan's countryside will have evolved for those conditions. America's ecology has not had a similar amount of time to adapt to the loss of the giant bison herds, et cetera.