Eating plants directly instead of feeding them to animals is clearly much more efficient, requiring much fewer animal deaths as well as plant deaths to sustain a human.

That is why in my third paragraph I mentioned that it was easier to sustain in the long term.

If plants are sentient, the moral argument for veganism is even stronger.

In my view this just feels like justifying a less deadly mass killing for a more deadly mass killing. They both have their consequences.

For example I think it is just as bad that due to our consumerist society we have to over harvest the land that we work on and grow plants in ways that make them more vulnerable to disease and other things that they would be less susceptible to if we didn't try to optimize their production. This is something that wouldn't change if we all suddenly became vegan we would also need to change our culture of consumption.

And this is why again my argument is not that we should just try and find an optimal utilitarian equation of how many lives are worth killing to sustain society but instead find a way to live that doesn't over exploit the ecosystem that we live in and doesn't go out of its way to do unnecessary harm to life.