Hello Andrew, I hope you are doing well. Literally, a goad is a stick with a pointed or electrically charged end, for driving cattle, oxen, etc. So, in this context, a goad is anything that acts as a spur or incitement to drive people to innovate. That's my interpretation, I hope it helps. Best regards.

The meaning is not very well expressed. I don't recommend trying to understand it too much - the confusion won't disappear! A correct way to say it is: "Their presence is enough (of a goad/an incentive)"