Keep in mind that immigration is actually a small part of this; the much much more important element is birth rates. The core issue in the US is that we made promises based on an economy where the baby boom generation was working to support their parents in retirement, but we're going to need to pay up in an economy where millennials are working to support the baby boom generation in retirement.

> A more robust, sustainable solution is to improve productivity via other means (including automation).

Sure, that would be nice. It's also completely impossible. Productivity growth has never, ever, ever grown fast enough to bail us out of the hole we're in now, and we have zero (repeat, zero) ideas on how we could possibly change that.

Productivity growth will not save us.

> What you're describing is a pyramid scheme. Get more and more new people in to pay for those already there

That's how retirement works in most countries. The tax burden mostly falls on the "productive age" (18-65), so until automation pays as much taxes as the humans it replaces (corporate tax dodging considered), retirees in countries with shrinking populations are screwed.

or just be ok with having less shit.