I bet the number of vegetarians would go up quite a bit if people had to slaughter animals themselves if they wanted meat. Our society is pretty good at hiding the dirty work from people.
My parents both grew up on farms where they slaughtered their own animals. They ate meat maybe once a week or less. So at a minimum meat consumption would go down.
I suspect the reason why they ate meat rarely was because it was expensive (even when it's your animal, it still has a cost), not because they were squeamish about it.