I think the idea that there’s still so much about nutrition we don’t know is a very reasonable take and a good argument against removing animal products from our diet
Of course there is a conversation to be had, though I think there's pretty clear evidence individuals can function just fine without animal consumption. But the idea that "society would collapse"? That seems to be going just a tad bit beyond what I would consider a "very reasonable take".
I think it would be easier to argue that our addiction to meat consumption is one culprit fueling society's collapse already given the environmental and ecological impact that meat production creates.