The phrase "not a question of $x" does not mean $x can't be asked at all, but that the question is unimportant.

In this case, cows exist, therefore thermodynamics is resolved to "yes you can make a cow for at most the cost of a cow, in the general case", and I don't need to show detailed working to know that. Existence proofs make it obviously "not a question of" any law of nature, including thermodynamics, that we can't reproduce that existence proof synthetically.

This doesn't tell me how to do it, how to make it cheap enough for anyone to care, what the actual ultimate limits are, etc.

I don't think they were denying thermodynamics. Merely denying that it trumps economics.