Well, we are all very curious about this topic, and I found some pretty interesting answers in Homo Deus by Yuval Noah Harari. Read my review here:
https://steemit.com/science/@herverisson/homo-deus-part-3-homo-sapiens-loses-control
Basically, the 1% elite always needed humans to produce wealth and to wage war. Now, they don't even need basic humans for that! Drones and machines do all of it :) Pretty handy right?