The thing that got me to significantly reduce my dairy consumption was

1. Being exposed to vegetable milk (first soy then almond) by my roommates
2. Not keeping fresh milk in the apartment because it kept going bad
3. Losing the ability to gracefully digest lactose

I eat much less cow now because of cute internet cow videos.

Anyways, I think if 5 people reduce their consumption by 30% that’s more impactful than 1 person reducing their consumption by 100%. (Math caveat: assuming each person has the same baseline level of consumption. 5 vegans reducing their consumption by 30% won’t do squat).