These are people in some of the poorest countries like Bangladesh. Are pea proteins cost effective and available in sufficient enough quantities to feed all these people? Other people brought up that it isn't just about the protein but other essentials things like amino acids.
I don't know the details but look at what Slippery_John said in his comment:
> Well yes, but actually no. Not all proteins are equal, they have different quantities of different kinds of amino acids. Humans need 9 distinct amino acids for a healthy diet, and animal proteins are by far the easiest source of "complete proteins" from a single source. It's absolutely possible to get plant-based complete proteins (e.g. soy or quinoa), but often that involves deliberately mixing different protein sources to get a complete balance.