The key element is the firm. Firms begin, and grow, and are initially small, being expressions of the creativity of an innovative entrepreneur, a socially positive role. When a firm reaches a size such that it needs to seek capital from the market for further expansion, under capitalism the innovative entrepreneur loses control to a board of directors, who represent the interests of the capital owners. The electoral rights of these four constituencies need to be adjusted to reflect their degree of dependence on the ongoing viability of the firm. This adjustment process is the role of the democratic State, and it should be exercised at an appropriate level, local, regional or national, depending on the scale of the firm.
Workers always get strong representation.
By recognising the role of local, regional, national and specialist organised pension funds as the prime sources of capital, and ensuring that such funds were democratically structured. There certainly is a role for the State in such a model, but is is as a referee rather than as a player. As a player, the State is of questionable agility. There are features in the above which have been partially developed in the co-operative movement, and in the 'industrial democracy' movement, but I am not aware of any implementation where the quite complex interplay of constituency interests implied by the above has been fully explored. The boat has been missed in the various Eastern 'privatisation' schemes, which lacked a friendly State environment, and were sensitive to manipulation by criminal and speculative elements.