Even in our fabulously wealthy societies, people are mostly worried about paying their bills, taking care of their families, and putting food on the table, not in getting together in a quixotic enterprise and paying for thousands of kilometers of communal fiber. Also like in most communist utopias what would probably happen is that the control infrastructure would be captured by special interest groups and now you’ve traded one evil for another, but in addition you’re left holding the capex bag and you’re poorer for it.