OP said “more people would be vegan” which I think is strictly true. Everyone? No. Would a lot of people reduce their meat consumption from the currently obscene 150+ animals per year (average American)? Probably.

I probably eat a thousand anchovies a year alone.

But anyway yes, most of the specific individuals animals killed are chickens and water creatures of various types.

Here's a pretty good analysis based on USDA data. Prediction: "Seafood don't count! for handwavehandwave reasons!"

What you are missing is the industrial process we put together in the last 70 years to produce more meat; cheaper and faster.

Those are weird, and inhuman.

Those technics make most people uncomfortable. If not, the amount of antibiotics we have to pump into the animal to keep them healthy will hirk another slice of the public.

A data point here is the % of depression in slaughter house worker. Those are the one that are exposed for real.

Not a wet meat market worker, not a fancy butcher.

I don't think it turned many people off milk and cheese. Actually the grossest field trip we ever went on was to a potato chip factory, the stink of rotten potatoes was overwhelming. They never took us to a pig or chicken farm though, I've been to a few at other times and those would have beat the chip factory easily. A lot of people who grow up around cows say they appreciate the small (I do, to an extent) but I've never heard anybody say that about pigs or chickens.

But showing people factory farms, I think, is less likely to make people become vegans than it is to make people agitate for more humane forms of slaughter.

But I should admit my bias here: I am not a vegetarian (although I don't eat a great deal of meat either) and so I'm not upset that animals are killed for food. But I get very worked up about animals being tortured whether they're ending up as food or not, so I'm ascribing to "most people" what I feel myself, which is always a bit questionable.