Unless the block maker has an infinitely fast connection to it's hashpower OR it's hashpower is not parallelized at all, that's not strictly true -- it WILL orphan its own blocks because two hashing units will find solutions in the time it takes to communicate that solution to the block maker and to the rest of the hashing units.

That's getting into "how many miners can dance on the head of a pin" territory, though. I don't think we know whether the communication advantages of putting lots of hashing power physically close together will outweigh the extra cooling costs of doing that (or maybe some other tradeoff I haven't thought of). That would be a fine topic for another paper....

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