I am quite confident that humans are capable of evolving into a vegan species within a very short time.
There is evidence that quantum evolutionary leaps occur in times of crisis such as our global population is experiencing.
So, I see the vegan cause as a very winnable battle.
The vegan ideal also contains within it the power to solve a multitude of human problems (perhaps all of them, if you think about it honestly enough), as I explained in a previous article, The Vegan Solution.
If our species became herbivorous (which could end up happening soon, due to necessity, if nothing else), it would indicate such a major advancement in our collective mentality that the future would suddenly appear amazingly hopeful, in ways that we can not yet imagine.
I think the evolution of the population towards a herbivorous diet is not just imminent, but it is already occurring. The growth of the vegan population, and the increasing occurrences of animal-based diseases are signs of the change that is coming.
I also believe that the time is approaching where we will have no choice but to embrace the vegan way of life. It won’t happen all at once, but it might happen a lot sooner than we can currently imagine. This is how evolutionary leaps occur.
As John Stuart Mill articulated so eloquently:
“It often happens that the universal belief of one age, a belief from which no one was free, or could be free without an extraordinary effort of genius or courage, becomes to a subsequent age, so palpable an absurdity that the only difficulty is to imagine how such an idea could ever have appeared credible.”