I don't presume that brain emulation will come first and be significant, and indeed think that it probably won't.

OK, good to know. The idea in the paper is attributed to "Many scientists".

Regarding Malthusian competition, check out "burning the cosmic commons".

Yes, I am familiar with that. If you don't like what natural selection offers, one wonders just how slow, bloated and inefficient a civilisation is considered to be desirable - and how much of it would survive eventual contact with aliens.

The monopolies commission you describe would be a singleton under Bostrom's account, capable of overcoming any local challenge to its authority.

Yes, that is true.