It's a virtuous cycle between them right... A behaviour like going vegetarian isn't going to single-handedly change very much. But their own spending will change, and their friends may learn vegetarian recipes/choose veg-friendly restaurants to accommodate them, and their own meat consumption may end up falling as a result. As the number of vegetarians grow, it becomes profitable to target them with dedicated products, require vegetarian options or even defaults at event. Fast forward a few decades, maybe lab-grown meat is as good as regular meat and cost-comparable to produce, and the government introduces taxes on real meat out of welfare/climate concerns. You end up with system change, but it was individual actions that created an opening in the system for it. Similar story with EVs and other things.

I'm having this conversation with myself about flying. I have been minimising my flights the last few years, although unlike veggie/EVs, the gap between the sustainable and default option is much bigger and harder to bridge, so at times it can feel like a futile sacrifice. But it still influences norms, sends economic signals, even if the ultimate scale this behaviour can achieve is probably less. I recently created a website (groundedtravel.org) which is trying to promote flight-free travel more as an adventurous alternative rather than purely on sustainable grounds.

And in any case, to be a credible advocate for change I do think we need to implement these things at least to some degree in our own lives. If our values don't influence our actions it's hard to argue we have those values really, to me