Exactly! We got ahead of ourselves. Agriculture is really useful in some regards, but it needs some additional adaptations that just ... didn't happen at the same rate. (The one that I always think of is how the switch from nomadic to stationary lifestyles led to serious problems with sanitation. When you're on the go, you don't really need to worry so much about where you put your poop, because it tends to decompose quickly enough. If you build a house and live there all year, that's a lot of poop piling up. Took thousands of years to even START figuring out that was a problem.)