Along with agriculture came animals, and the animals settled in one place.

With farming came animals, and with animals came settling down and staying in one location. So, how does this have anything to do with invention and innovation? Everything. Anyone who's ever farmed, even if it's planting a half dozen tomato plants in your backyard, knows that you usually harvest way more than you could possibly eat, a surplus. Farming yielded plenty of food, with enough to store, trade, and eat. In other words, not everyone needed to be farmers.