Very little stock market wealth is held by pension funds on behalf of workers, as opposed to the already wealthy. See https://www.pensionsage.com/pa/Pension-scheme-holding-less-t..., for example. And the value on these schemes are disproportionately held by those who own and/or run companies rather than those who work in them: the Small Self-Administered Scheme is a popular means of UK tax avoidance for business owners who would like their capital gains tax free, and assets held in these schemes (on trust for the owner) will also be included in these figures.

Returns on capital flow, unsurprisingly, to those with capital. And the concentration of capital in fewer and fewer hands is precisely the issue that people are objecting to.