However: In that very same perfect system, the individual is also compensated for exactly 100% of the added value.
If they then spend it on personal consumption, they capture all the value of their work for personal benefit.
Society is improved by that exact amount only if you include that workers well-being in the calculation. Otherwise, it's exactly zero.
But the effective altruist community has already come up with a perfectly valid yet somewhat disappointing answer: "earn to give", i. e. try to make as much money as possible, then spend as much of it as possible on others' wellbeing.