Agriculture reduced the global human economy/resource production doubling time from 100,000s of years to 1000s of years. Industrial revolution dropped it from 1000s to 10s or even 1s. If AI follows the same path it becomes 0.1 - 0.01 years.
Your 401k wouldn't need 40 years to build a comfortable retirement, only 4 weeks.
I just watched a video that convincingly showed that it is energy and energy alone that determines the production growth of humanity. Until the day AI can "generate" stuff (you know, something out of nothing) it can only at best streamline existing production, which is entirely capped by energy limits.
We may drown in oceans of audio, video, novels, poems, films, porn, blue prints, chemical formulas, etc. dreamed up by AI, but to realize these designs, blueprints, formulas, drugs, etc. ("production") we need to actually resource the materials, and have the necessary energy to make it happen.
It will not be AI that catapults humanity. It can definitely mutate human society (for +/-) but it will not (and can not) result in any utopian outcomes, alone. But something like cold fusion, if it actually becomes a practical matter, would result in productivity that would dwarf anything that came before (modulo material resource requirements).
Your 401k wouldn't need 40 years to build a comfortable retirement, only 4 weeks.