It seems to me that clustering quantum computers is likely to have the same effect as clustering classical computers, since there is no quantum effect involved in the clustering.

It'll be interesting to see what consequences this result will have on quantum computing. If the tipping point between the quantum and the classical world is something fundamental to physics and cannot be overcome, that means there is a limit to how big quantum computers can be. And if there is such a limit, will the largest possible quantum computers be any useful or does it mean that the whole field of quantum computing amounted to nothing?

There is nothing that says that a functional language needs to have automatic memory management (such as garbage collection). The kind of language design I have in mind would not.