>There is nothing whatsoever preventing automation of craft beer

In theory there's nothing to prevent the automation of any process. The question is cost.

For craft beer there's 10,000 different kinds for every 10 million liters drunk, all with a completely different brewing process and consumer tastes keep changing in this market because consumers seek novelty.

Whereas for Budweiser there's just one, unchanging process.

So yes, it is much harder to automate than Budweiser brewing and is much more labor intensive.

It's far from the only market where this happens, too.