The US is adding 1.x million people per year, on a decline. The addition is entirely meaningless against the context. The US is also aging persistently, as with most of its peers.
Exaggerated, your premise rests on: the US is not exactly like the Japan scenario, it's 98-99% like the Japan scenario. Point being, that tiny population expansion is trivial and will be mostly gone soon anyway.
The population addition in question is majority lower income, lower education oriented in numbers. The US has an inverted immigration system vs eg Canada or Australia (they focus on higher income, higher education, skill-based immigration). That fact further debases the potency / value of the population expansion. US education has been eroding for decades in terms of quality, so those lower income, lower education new immigrants are entering the US at a particularly mediocre time for their purposes (and they'll also simultaneously run into the automation, robotics, AI buzzsaw that is in the first or second inning; further devaluing what that population expansion brings to the table).
Exaggerated, your premise rests on: the US is not exactly like the Japan scenario, it's 98-99% like the Japan scenario. Point being, that tiny population expansion is trivial and will be mostly gone soon anyway.
The population addition in question is majority lower income, lower education oriented in numbers. The US has an inverted immigration system vs eg Canada or Australia (they focus on higher income, higher education, skill-based immigration). That fact further debases the potency / value of the population expansion. US education has been eroding for decades in terms of quality, so those lower income, lower education new immigrants are entering the US at a particularly mediocre time for their purposes (and they'll also simultaneously run into the automation, robotics, AI buzzsaw that is in the first or second inning; further devaluing what that population expansion brings to the table).