It could be clearer throughout, whether he's talking per capita or overall.
Data is selective and ignores resource utilization shifts. Example: In the 1940s crop acreage decoupled from crop yield, he says. Great! Instead it coupled to petroleum and energy, he doesn't say. American farms today are in the business of converting fossil fuels to food. For example, the 1940s are when when cheap internal-combustion tractors started being mass-produced, thanks to all that spare manufacturing capacity left over after the war. There's also a graph where he looks at "every input" into growing corn, even down to the phosphates, while scrupulously avoiding any talk of fuel or energy.
A resource shift of a different kind: efficiency gains in chicken production are due mostly to inhumane factory farm conditions. (Ones to which pork & beef are less amenable, hence chicken outdoes them.)
Wood is no longer used for railroad ties, because we use concrete. Which has its own problems! The point in most of this kind of example is that we stop using A because B comes along to fill the void. Nobody uses paper anymore, but they sure use a lot more lithium than they used to. And so on.
Finally, and speaking of stepping in to fill the void: ctrl-F - "China" - 1 match. The single mention is to refer to it as a developing country, not to acknowledge it as the present-day location of much of the USA's manufacturing.