Eventually we will learn, and practice, that growing a single crop in gigantic monocultures like this is a bad idea. At what point do we run out of other varie

Eventually we will learn, and practice, that growing a single crop in gigantic monocultures like this is a bad idea. At what point do we run out of other varieties of crops to take genes from? I think the sustainable end point are genetically engineered yeasts grown in sterile indoor pools that takes in sunlight, growth medium and minerals to product some kind of nutritionally complete Soylent for humans to eat.