Because in a well organized society where wealth accumulation is not by corruption, then by definition it would be by creating value, which benefits everyone.

The alternative is something like oligarchs that extract wealth because of state granted monopolies, corporatism that strangles competition with anti competitive regulation, etc. The accumulation of wealth is all out of proportion and possibly not even correlated in those cases with the production of actual value.

Wealth is accumulated by capturing value, not by creating it.