Both Carl and Robin presume that brain emulations will be economically significant - which seems very unlikely. We may eventually be able to back up minds, but by then we will have intelligent machines by other means that will be doing most of civilisation's cognitive work.

Carl's section about "unrestrained Malthusian competition" seems rather paranoid. It exhibits "cold-war"-era thinking. Advanced organisms are much more likely to trade with one another - which seems relatively unlikely to result in existential risk.

Both parties avoid discussion of what will probably determine whether such a single large entity forms or not - a cosmic monopolies and mergers commission. Robin presumably thinks such a thing will be unnecessary - on the grounds that coordination is so hard. Why Carl doesn't discuss it is less obvious. Perhaps he thinks it is obviously a product of a primitive political system. Today, some political thinking suggests that preventing large-scale cooperation is desirable, and that deliberate fragmentation is the way to go. If that perspective continues to dominate, it seems relatively unlikely that a unified system will arise - since the monopolies and mergers commission would destroy any such unity.