I think the basic idea could be done for a fraction of the cost. Assuming the island didn't have cars you could have conventional buildings with narrow streets

I think the basic idea could be done for a fraction of the cost. Assuming the island didn't have cars you could have conventional buildings with narrow streets that would be used by snowmobiles in the winter and bicycles in the summer. Ever been to downtown Montreal? They have all the buildings inter-connected either with tunnels below or skyways above. It all works pretty well in a region with long, cold winters.