this is a common criticism, that it doesn't scale.
but you're using corporations (walmart) and their organisational structures to argue this, when those are not democratic organisations (not even representative democracy). So ofc they can't work with democracy, they didn't come from it.
the same goes for the problems of nations and resource distribution - at no point was the system of commodity trade & exchange created or agreed upon democratically, the same is true of nation states.
in fact i'd predict that under dd, national borders would naturally drastically change or disappear, and the resource exchange mechanism (the world economy) would become much better adapted to fairly solve the distribution issue.
"the municipal transportation council wants to construct a new rail line to ease congestion, that’s treated the same as if some train expert had convincingly argued the case to the public and the public had directly voted to build the new line."
do you mean in this example, that the public would get a direct vote upon the proposal, or just that it would be treated as if that were the case because the public voted on the institution?
and how can we treat an institution as equivilant to a train expert, unless it is staffed by train experts? in which case is your point that the public would vote a technocratic institution in, and the composition of it, and thereafter cede decisions to them?
also, with your three reconciliations:
isn't it the case that material conditions mean that we do not have a right to rule ourselves, at least isn't it more complicated than that - we a are helpless for time and cannot do so, and some people are disabled and cannot. our right to self rule is necessarily bounded by our physical powers and our relation to society surely, such that we can't treat 'everyone has a right to self rule' as a fundamental proposition, at least in all aspects of human experience? or do you mean just politically?
Why? We consider it necessary for the function of government to do all sorts of things requiring great effort and cost, why is this any different? I agree regarding every little issue, but I'd say at least every significant issue is possible once a month?
yes, but i think this is resolvable via the implemented structure of dd. So you don't get a vote on everything, just things that affect you. You can end up voting on something that doesn't directly affect you, but not on something that doesn't directly or indirectly affect you.
i struggle with the solution you present with creating powerless institutions, like you say i think it would be create appropriate checks and balances - they need some power to function.